January 1964 - Resigns from NASA's astronaut program.

1964 - Enters the Ohio Democratic primary to challenge the incumbent Democratic senator, Stephen M. Young but withdraws after being injured in a fall.

1965 - Retires from active service in the U.S. Marine Corps to enter the business world.

1965-1970 - He is vice president and then president of Royal Crown Cola.

1970 - Glenn enters the Democratic primary for the U.S. Senate but loses.

November 1974-1999 - Elected to the U.S. Senate and serves four consecutive terms (D-Ohio).

1978 - Chief author of the Nuclear Nonproliferation Act of 1978, prohibiting the sale of nuclear equipment to nations that currently have none.

1983-1984 - Runs unsuccessfully for the Democratic presidential nomination for the 1984 election. He drops out of the race after failing to win any early primaries or caucuses.

1987-1995 - Glenn is chairman of the Senate Governmental Affairs Committee, and sits on the Foreign Relations, Armed Services Committees and the Special Committee on Aging.

February 20, 1997 - Glenn announces on the 35th anniversary of his orbit around the earth that he will not run for re-election in the U.S. Senate.