Q: Who was the last sitting congressman or senator to be elected president?
A: John F. Kennedy was the last president to have moved directly from Congress to the White House.
FULL ANSWER
On Dec. 22, 1960, Kennedy resigned as senator of Massachusetts to take his place as the 35th U.S. president. No other senator or congressman has made that same transition since. In fact, only three men have accomplished this rare feat.
The first, James A .Garfield was serving as a representative of Ohio when he won the 1880 presidential election. Garfield had been elected to the senate in 1880 as well, but declined the position to assume the role of president.
After winning the 1920 election, Warren G. Harding resigned from his post as senator of Ohio to become the 29th U.S. president .
In all, 15 senators and 18 members of the House have gone on to become president, but only Garfield, Harding and Kennedy were sitting members of Congress when they were elected to the White House.
– D’Angelo Gore
Update, July 31: We originally said that 17 members of the House went on to serve as president, citing the Office of the Clerk of the House of Representatives as our source. However, an astute reader pointed out that the Office of the Clerk had missed one congressman who was later commander in chief, Andrew Johnson. The article has been changed to reflect this.
Sources
United States Senate. "Senators Who Became President," 4 Feb. 2008.
Office of the Clerk. "House Members Who Became President or Presidential Candidate." United States House of Representatives, 4 Feb. 2008.