Heinrich Luitpold Himmler was born in Munich on 7 October 1900 into a conservative middle-class Roman Catholic family. His father was Joseph Gebhard Himmler (17 May 1865 – 29 October 1936), a teacher, and his mother was Anna Maria Himmler (née Heyder; 16 January 1866 – 10 September 1941), a devout Roman Catholic. Heinrich had two brothers, Gebhard Ludwig (29 July 1898 – 22 June 1982) and Ernst Hermann (23 December 1905 – 2 May 1945).

Himmler's diary, which he kept intermittently from the age of 10, shows that he took a keen interest in current events, dueling, and "the serious discussion of religion and sex".

In 1915, he began training with the Landshut Cadet Corps.

His father used his connections with the royal family to get Himmler accepted as an officer candidate, and he enlisted with the reserve battalion of the 11th Bavarian Regiment in December 1917.

In November 1918, while Himmler was still in training, the war ended with Germany's defeat, denying him the opportunity to become an officer or see combat. After his discharge on 18 December, he returned to Landshut. After the war, Himmler completed his grammar-school education.

From 1919–22, he studied agronomy at the Munich Technische Hochschule (now Technical University Munich) following a brief apprenticeship on a farm and a subsequent illness.

During Himmler's second year at university, Himmler redoubled his attempts to pursue a military career. Although he was not successful, he was able to extend his involvement in the paramilitary scene in Munich. It was at this time that he first met Ernst Röhm, an early member of the Nazi Party and co-founder of the Sturmabteilung ("Storm Battalion"; SA). Himmler admired Röhm because he was a decorated combat soldier, and at his suggestion, Himmler joined his antisemitic nationalist group, the Bund Reichskriegsflagge (Imperial War Flag Society).

In 1922, Himmler became more interested in the "Jewish question", with his diary entries containing an increasing number of antisemitic remarks and recording a number of discussions about Jews with his classmates. His reading lists, as recorded in his diary, were dominated by antisemitic pamphlets, German myths, and occult tracts.

After the murder of Foreign Minister Walther Rathenau on 24 June, Himmler's political views veered towards the radical right, and he took part in demonstrations against the Treaty of Versailles.

Hyperinflation was raging, and Himmler's parents could no longer afford to educate all three sons. Disappointed by his failure to make a career in the military and his parents' inability to finance his doctoral studies, Himmler was forced to take a low-paying office job after obtaining his agricultural diploma. He remained in this position until September 1923.

Himmler joined the Nazi Party (NSDAP) in August 1923, receiving Party number 14303. As a member of Röhm's paramilitary unit, Himmler was involved in the Beer Hall Putsch—an unsuccessful attempt by Hitler and the NSDAP to seize power in Munich. This event would set Himmler on a life of politics. He was questioned by the police about his role in the putsch but was not charged because of insufficient evidence. However, he lost his job, was unable to find employment as an agronomist, and had to move in with his parents in Munich. Frustrated by these failures, he became ever more irritable, aggressive, and opinionated, alienating both friends and family members.

In 1923–24, Himmler, while searching for a world view, came to abandon Catholicism and focused on the occult and antisemitism. Germanic mythology, reinforced by occult ideas, became a religion for him. Himmler found the NSDAP appealing because its political positions agreed with his own views. Initially, he was not swept up by Hitler's charisma or the cult of Führer worship. However, as he learned more about Hitler through his reading, he began to regard him as a useful face of the party, and he later admired and even worshipped him. To consolidate and advance his own position in the NSDAP, Himmler took advantage of the disarray in the party following Hitler's arrest in the wake of the Beer Hall Putsch.

From mid-1924, Himmler worked under Gregor Strasser as a party secretary and propaganda assistant. Traveling all over Bavaria agitating for the party, he gave speeches and distributed literature.

Himmler was Placed in charge of the party office in Lower Bavaria by Strasser from late 1924, he was responsible for integrating the area's membership with the NSDAP under Hitler when the party was re-founded in February 1925.

Himmler joined the Schutzstaffel (SS) as an SS-Führer (SS-Leader); his SS number was 168.

The SS, initially part of the much larger SA, was formed in 1923 for Hitler's personal protection and was re-formed in 1925 as an elite unit of the SA. Himmler's first leadership position in the SS was that of SS-Gauführer (district leader) in Lower Bavaria from 1926.

Strasser appointed Himmler deputy propaganda chief in January 1927. As was typical in the NSDAP, he had considerable freedom of action in his post, which increased over time. He began to collect statistics on the number of Jews, Freemasons, and enemies of the party, and following his strong need for control, he developed an elaborate bureaucracy.

In September 1927, Himmler told Hitler of his vision to transform the SS into a loyal, powerful, racially pure elite unit. Convinced that Himmler was the man for the job, Hitler appointed him Deputy Reichsführer-SS, with the rank of SS-Oberführer.

By 1930 Himmler had persuaded Hitler to run the SS as a separate organization, although it was officially still subordinate to the SA.

In September of 1930, Himmler was first elected as a deputy to the Reichstag.

Himmler's organized, bookish intellect served him well as he began setting up different SS departments. In 1931 he appointed Reinhard Heydrich chief of the new Ic Service (intelligence service), which was renamed the Sicherheitsdienst (SD: Security Service) in 1932. He later officially appointed Heydrich his deputy. The two men had a good working relationship and a mutual respect

Effective 1 January 1933, Hitler promoted Himmler to the rank of SS-Obergruppenführer, equal in rank to the senior SA commanders.

The Nazi Party's rise to the power provided Himmler and the SS an unfettered opportunity to thrive. By 1933, the SS numbered 52,000 members. Strict membership requirements ensured that all members were of Hitler's Aryan Herrenvolk ("Aryan master race"). Applicants were vetted for Nordic qualities—in Himmler's words, "like a nursery gardener trying to reproduce a good old strain which has been adulterated and debased; we started from the principles of plant selection and then proceeded quite unashamedly to weed out the men whom we did not think we could use for the build-up of the SS." Few dared mention that by his own standards, Himmler did not meet his own ideals.

In March 1933, less than three months after the Nazis came to power, Himmler set up the first official concentration camp at Dachau.

In March 1933, Reich Governor of Bavaria Franz Ritter von Epp appointed Himmler chief of the Munich Police. Himmler appointed Heydrich commander of Department IV, the political police. Thereafter, Himmler and Heydrich took over the political police of state after state; soon only Prussia was controlled by Göring.

Göring had created a Prussian secret police force, the Geheime Staatspolizei or Gestapo in 1933, and appointed Rudolf Diels as its head. Göring, concerned that Diels was not ruthless enough to use the Gestapo effectively to counteract the power of the SA.

Hitler had stated that he did not want it to be just another prison or detention camp. Himmler appointed Theodor Eicke, a convicted felon and ardent Nazi, to run the camp in June 1933. Eicke devised a system that was used as a model for future camps throughout Germany. Its features included isolation of victims from the outside world, elaborate roll calls and work details, the use of force and executions to exact obedience, and a strict disciplinary code for the guards. Uniforms were issued for prisoners and guards alike; the guards' uniforms had a special Totenkopf insignia on their collars.

On 2 June Himmler, along with the heads of the other two Nazi paramilitary organizations, the SA and the Hitler Youth, was named a Reichsleiter, the second-highest political rank in the Nazi Party.

Hitler decided on 21 June that Röhm and the SA leadership had to be eliminated. He sent Göring to Berlin on 29 June, to meet with Himmler and Heydrich to plan the action. Hitler took charge in Munich, where Röhm was arrested; he gave Röhm the choice to commit suicide or be shot. When Röhm refused to kill himself, he was shot dead by two SS officers.

On 1 August 1934, Hitler's cabinet passed a law which stipulated that upon von Hindenburg's death, the office of president would be abolished and its powers merged with those of the chancellor. Von Hindenburg died the next morning, and Hitler became both head of state and head of government under the title Führer und Reichskanzler (leader and chancellor).

By the end of 1934, Himmler took control of the camps under the aegis of the SS, creating a separate division, the SS-Totenkopfverbände.

On 15 September 1935, Hitler presented two laws—known as the Nuremberg Laws—to the Reichstag. The laws banned marriage between non-Jewish and Jewish Germans and forbade the employment of non-Jewish women under the age of 45 in Jewish households. The laws also deprived so-called "non-Aryans" of the benefits of German citizenship. These laws were among the first race-based measures instituted by the Third Reich.

Initially, the camps housed political opponents; over time, undesirable members of German society—criminals, vagrants, deviants—were placed in the camps as well. In 1936 Himmler wrote in the pamphlet "The SS as an Anti-Bolshevist Fighting Organization" that the SS was to fight against the "Jewish-Bolshevik revolution of subhumans".

On 17 June 1936 Hitler decreed the unification of all police forces in the Reich and named Himmler Chief of German Police and a State Secretary in the Ministry of the Interior.

A Hitler decree issued in December 1937 allowed for the incarceration of anyone deemed by the regime to be an undesirable member of society. This included Jews, Gypsies, communists, and those persons of any other cultural, racial, political, or religious affiliation deemed by the Nazis to be Untermensch (sub-human). Thus, the camps became a mechanism for social and racial engineering. By the outbreak of World War II in autumn 1939, there were six camps housing some 27,000 inmates. Death tolls were high.

When Hitler and his army chiefs asked for a pretext for the invasion of Poland in 1939, Himmler, Heydrich, and Heinrich Müller masterminded and carried out a false flag project code-named Operation Himmler. German soldiers dressed in Polish uniforms undertook border skirmishes which deceptively suggested Polish aggression against Germany. The incidents were then used in Nazi propaganda to justify the invasion of Poland, the opening event of World War II.

With Hitler's approval, Himmler re-established the Einsatzgruppen in the lead-up to the planned invasion of the Soviet Union.

By early 1941, following Himmler's orders, ten concentration camps had been constructed in which inmates were subjected to forced labor. Jews from all over Germany and the occupied territories were deported to the camps or confined to ghettos.

Initially, the victims were killed with gas vans or by firing squad, but these methods proved impracticable for an operation of this scale. In August 1941, Himmler attended the shooting of 100 Jews at Minsk. Nauseated and shaken by the experience, he was concerned about the impact such actions would have on the mental health of his SS men. He decided that alternate methods of killing should be found.

In late 1941, Hitler named Heydrich as Deputy Reich Protector of the newly established Protectorate of Bohemia and Moravia. Heydrich began to racially classify the Czechs, deporting many to concentration camps. Members of a swelling resistance were shot, earning Heydrich the nickname "the Butcher of Prague". This appointment strengthened the collaboration between Himmler and Heydrich, and Himmler was proud to have SS control over a state. Despite having direct access to Hitler, Heydrich's loyalty to Himmler remained firm.

Nazi racial policies, including the notion that people who were racially inferior had no right to live, date back to the earliest days of the party; Hitler discusses this in Mein Kampf. Somewhere around the time of the German declaration of war on the United States in December 1941, Hitler finally resolved that the Jews of Europe were to be "exterminated".

Germany subsequently invaded Denmark and Norway, the Netherlands, and France, and began bombing Great Britain in preparation for Operation Sea Lion, the planned invasion of the United Kingdom. On 21 June 1941, the day before the invasion of the Soviet Union, Himmler commissioned the preparation of the Generalplan Ost (General Plan for the East); the plan was finalized in July 1942. It called for the Baltic States, Poland, Western Ukraine, and Byelorussia to be conquered and resettled by ten million German citizens.

On 26 September 1944 Hitler ordered Himmler to create special army units, the Volkssturm ("People's Storm" or "People's Army"). All males aged sixteen to sixty were eligible for conscription into this militia, over the protests of Armaments Minister Albert Speer, who noted that irreplaceable skilled workers were being removed from armaments production. Hitler confidently believed six million men could be raised, and the new units would "initiate a people's war against the invader".

On 6 June 1944, the Western Allied armies landed in northern France during Operation Overlord. In response, Army Group Upper Rhine (Heeresgruppe Oberrhein) group was formed to engage the advancing US 7th Army (under command of General Alexander Patch) and French 1st Army (led by General Jean de Lattre de Tassigny) in the Alsace region along the west bank of the Rhine. In late 1944, Hitler appointed Himmler commander-in-chief of Army Group Upper Rhine.

On 1 January 1945, Hitler and his generals launched Operation North Wind. The goal was to break through the lines of the US 7th Army and French 1st Army to support the southern thrust in the Ardennes offensive, the final major German offensive of the war. After limited initial gains by the Germans, the Americans halted the offensive. By 25 January, Operation North Wind had officially ended.

On 25 January 1945, despite Himmler's lack of military experience, Hitler appointed him as commander of the hastily formed Army Group Vistula (Heeresgruppe Weichsel) to halt the Soviet Red Army's Vistula–Oder Offensive into Pomerania. Himmler established his command center at Schneidemühl, using his special train, Sonderzug Steiermark, as his headquarters.

In early 1945, the German war effort was on the verge of collapse and Himmler's relationship with Hitler had deteriorated. Himmler considered independently negotiating a peace settlement. His masseur, Felix Kersten, who had moved to Sweden, acted as an intermediary in negotiations with Count Folke Bernadotte, head of the Swedish Red Cross. Letters were exchanged between the two men, and direct meetings were arranged by Walter Schellenberg of the RSHA.

Himmler and Hitler met for the last time on 20 April 1945—Hitler's birthday—in Berlin, and Himmler swore unswerving loyalty to Hitler. At a military briefing on that day, Hitler stated that he would not leave Berlin, in spite of Soviet advances. Along with Göring, Himmler quickly left the city after the briefing.

On 21 April, Himmler met with Norbert Masur, a Swedish representative of the World Jewish Congress, to discuss the release of Jewish concentration camp inmates.

On 23 April, Himmler met directly with Bernadotte at the Swedish consulate in Lübeck. Representing himself as the provisional leader of Germany, he claimed that Hitler would be dead within the next few days. Hoping that the British and Americans would fight the Soviets alongside what remained of the Wehrmacht, Himmler asked Bernadotte to inform General Dwight Eisenhower that Germany wished to surrender to the Western Allies, and not to the Soviet Union.

On 27 April, Himmler's SS representative at Hitler's HQ in Berlin, Hermann Fegelein, was caught in civilian clothes preparing to desert; he was arrested and brought back to the Führerbunker.

On the evening of 28 April, the BBC broadcast a Reuters news report about Himmler's attempted negotiations with the western Allies. Hitler had long considered Himmler to be second only to Joseph Goebbels in loyalty; he called Himmler "the loyal Heinrich".

On 29 April—one day prior to his suicide—Hitler declared both Himmler and Göring to be traitors. He stripped Himmler of all of his party and state offices and expelled him from the Nazi Party.

On 21 May, Himmler and two aides were stopped and detained at a checkpoint in Bremervörde set up by former Soviet POWs. Over the following two days, he was moved around to several camps.

Himmler bit into a hidden potassium cyanide pill and collapsed onto the floor. He was dead within 15 minutes. Shortly afterward, Himmler's body was buried in an unmarked grave near Lüneburg. The grave's location remains unknown.