Biden was sworn in on January 5, 1973, by the secretary of the Senate Francis R. Valeo at the Delaware Division of the Wilmington Medical Center. Present were his sons Beau (whose leg was still in traction from the automobile accident) and Hunter and other family members. At 30, he was the sixth-youngest senator in U.S. history.
On 15 January 1973, all U.S. combat activities were suspended. Lê Đức Thọ and Henry Kissinger, along with the Provisional Revolutionary Government (PRG, the Viet Cong's government) Foreign Minister Nguyễn Thị Bình and a reluctant President Thiệu, signed the Paris Peace Accords on 27 January 1973.
In the lead-up to the ceasefire on 28 January, both sides attempted to maximize the land and population under their control in a campaign known as the War of the flags, fighting continued after the ceasefire, this time without US participation and continued throughout the year.
On 15 March 1973, Nixon implied the US would intervene again militarily if the North launched a full offensive, and Secretary of Defense James Schlesinger re-affirmed this position during his June 1973 confirmation hearings.
At the 1973 Academy Awards ceremony, Brando refused to accept the Oscar for his performance in The Godfather. Sacheen Littlefeather represented him at the ceremony. She appeared in full Apache attire and stated that owing to the "poor treatment of Native Americans in the film industry", Brando would not accept the award.
On April 3, 1973, Martin Cooper, a Motorola researcher and executive, made the first mobile telephone call from handheld subscriber equipment, placing a call to Dr. Joel S. Engel of Bell Labs, his rival. The prototype handheld phone used by Dr. Cooper weighed 1.1 kilograms (2.4 lb) and measured 23 by 13 by 4.5 centimetres (9.1 by 5.1 by 1.8 in). The prototype offered a talk time of just 30 minutes and took 10 hours to re-charge.
On April 20, 1973, Bufalino was arrested in a Scranton night club in an FBI raid, charged with interference with interstate commerce, obstruction of justice, gambling and transporting stolen property, but later released in $50,000 bail.
The first feature film to use digital image processing was the 1973 movie Westworld, a science-fiction film written and directed by novelist Michael Crichton, in which humanoid robots live amongst the humans. John Whitney, Jr, and Gary Demos at Information International, Inc. digitally processed motion-picture photography to appear pixelized in order to portray the Gunslinger android's point of view.
Wailers released the album Burnin' which included the song "I Shot the Sheriff". Eric Clapton was given the album by his guitarist George Terry in the hope that he would enjoy it. Clapton was suitably impressed and chose to record a cover version of "I Shot the Sheriff".
On 18 November 1973, Ben-Gurion suffered a cerebral hemorrhage, and was taken to Sheba Medical Center in Tel HaShomer, Ramat Gan. During the first week following the stroke, he received visits from many high-ranking officials, including Prime Minister Golda Meir. His condition began deteriorating on 23 November, and he died on 1 December at age 87.
In 1973, Carlos conducted a failed PFLP assassination attempt on Joseph Sieff, a Jewish businessman and vice president of the British Zionist Federation. On 30 December, Carlos called on Sieff's home on Queen's Grove in St John's Wood and ordered the maid to take him to Sieff. Finding Sieff in the bathroom, in his bath, Carlos fired one bullet at Sieff from his Tokarev 7.62mm pistol, which bounced off Sieff just between his nose and upper lip and knocked him unconscious; the gun then jammed and Carlos fled.