John Warner rejoined Hogan & Hartson after his decision not to seek a sixth term as U.S. Senator for the Commonwealth of Virginia. During his 30 years in the Senate, he served on the Senate Armed Services Committee, including three periods as Chairman, and was viewed as one of the most influential senators on military and foreign policy issues. At varying times, The Senator also served on the Senate Health, Education, and Pensions Committee; Committee on Homeland Security and Governmental Affairs; Select Committee on Intelligence (where he served as Vice Chairman for several years); Commerce Committee; Environment and Public Works Committee; and Rules Committee (where he served as Chair for several years). Most recently, he was the lead co-sponsor with Senator Joseph Lieberman (I-Conn.) on climate change legislation.

The Senator volunteered for two periods of active military duty: the first as an enlisted sailor in the final years of World War II (1945-46), and the second as a Lieutenant in the U.S. Marines during the Korean War (1950-52).

After completing his law degree at the University of Virginia School of Law, he clerked for The Honorable E. Barrett Prettyman, U.S. Court of Appeals for the District of Columbia Circuit. From 1955 to 1960, the Senator was an Assistant U.S. Attorney for the District of Columbia. He joined Hogan & Hartson as an associate in 1961 and became a partner in 1964.

He left Hogan & Hartson in 1969 when he was appointed, and confirmed by the Senate, as Under Secretary, and later as Secretary, of the U.S. Navy, positions he served in for a total of more than five years during the Vietnam War.

Between 1974 and 1976, the Senator served as Administrator for the American Revolution Bicentennial Administration, where he administered federal programs in all 50 states and with 22 foreign nations that participated in this historic 200-year anniversary of the founding of our nation.

Subsequently, he waged two years of political campaigning, winning election to his first of five Senate terms in November 1978. On January 3, 2009, he completed his fifth consecutive term and retired, establishing a record of being the second longest-serving U.S. Senator in the history of the Commonwealth of Virginia.