The secretary of the U.S. Navy between 1972 and 1974, Warner held the second-longest tenure for a Virginia senator, serving five terms between 1979 and 2009. He helped plan the United States' Bicentennial celebration in 1976 and was known for pushing back against his party's increasing conservative tone.
Warner was undersecretary of the Navy for three years before he was promoted to secretary in the administration of President Richard Nixon. His naval oversight tenure occurred at the height of the Vietnam War.
Before that, he was an enlisted sailor during the second world war and then served as a Marine Corps officer during the Korean War.
"Today, on behalf of the Department of Defense, we mourn the loss of Sen. John Warner and celebrate his life of extraordinary service to our country," Secretary of Defense Lloyd Austin said in a statement. "From his early days serving in the military to his distinguished careers at the Pentagon and in the United States Senate, Sen. Warner set an enduring example of principled leadership."
Warner often made decisions that both pleased and angered Republican colleagues. He supported Republican President Ronald Reagan's military buildup during the Cold War in the 1980s, especially Naval shipbuilding, which also benefited Virginia's economy.
In 1987, he broke ranks with Republicans as one of 15 GOP senators who opposed Reagan's nomination of Robert Bork to the U.S. Supreme Court. He also declined to support fellow Republican and controversial Iran-Contra figure Oliver North when he unsuccessfully ran for Virginia's other Senate seat in 1994.
He was known for independence as chair of the Senate Armed Services committee, pushed for legislation to ban the torture of alleged terrorists and opposed the so-called don't ask, don't tell policy of the Clinton administration.
He also supported the campaign of Democratic President Joe Biden, who said Warner "lived an extraordinary life of service and accomplishment." The two served together in the Senate for about three decades.
"The John Warner I knew was guided by two things: his conscience and our Constitution. And, when acting in accordance with both, he neither wavered in his convictions nor was concerned with the consequences," Biden said.
"Through his service in uniform and the Senate, John Warner deftly helped guide our ship of state. Today our hearts and prayers are with his family."
An attorney by training who attended the University of Virginia's law school with New York Sen. Robert Kennedy, Warner worked for Nixon during his presidential campaign in 1960, which he ultimately lost to John F. Kennedy.
Warner became Taylor's sixth and penultimate husband in 1976. The marriage lasted for six years.
"My lifestyle is now quite different," he said after the divorce in 1982.
Taylor married only once more after divorcing Warner. She died in 2011.
He had three children from his first marriage to Catherine Mellon, the granddaughter of banking and steel millionaire Andrew Mellon.