1959: Hired as an assistant district attorney in Philadelphia.
1964: Serves on the Warren Commission, which concludes that a lone assassin killed President John F. Kennedy.
1965: Runs successfully on Republican ticket for Philadelphia district attorney, even though he is a Democrat.
1967: Loses election for Philadelphia mayor.
1969: Elected to second term as district attorney.
1973: Loses bid for third term as district attorney.
1976: Loses GOP Senate primary.
1978: Loses GOP gubernatorial primary.
1980: Wins Pennsylvania's open U.S. Senate seat and joins new Republican majority in the chamber.
1986: Elected to second term in Senate.
1987: Helps defeat President Ronald Reagan's Supreme Court nomination of Robert H. Bork.
1991:âAggressively questions Anita Hill during Clarence Thomas' Supreme Court nomination hearing.
1992:âElected to third term in Senate.
1995:âAnnounces candidacy for president. Suspends campaign later that year amid fundraising difficulties.
1998: Elected to fourth term in Senate.
2004: Ekes out win in Senate GOP primary, beating U.S. Rep. Pat Toomey by 17,146 votes, or 1.6 percentage points. Wins a fifth term in November.
2005: Begins two-year term as chairman of Senate Judiciary Committee.
February 2009: Votes for Democrats' economic stimulus package, inflaming GOP sentiment against him.
April 15: Toomey announces he will mount another challenge to Specter in 2010 Senate GOP primary.
April 28: Specter announces he is changing party registration from Republican to Democrat.
Aug. 4: Democratic U.S. Rep. Joe Sestak announces his Senate candidacy.
May 18, 2010: Sestak defeats Specter in Democratic Party primary.
Dec. 22: Specter takes last vote in Senate.
Jan. 3, 2011: Senate term ends.
Oct. 19: In speech, Specter blames the tea party for removing GOP moderates, says Washington gridlock has become "like a war."
Aug. 28, 2012: Confirms that he is battling cancer again, calls it "another battle I intend to win."
Oct. 14: Son confirms Specter's death at his Philadelphia home of complications of non-Hodgkin lymphoma.