Born in Wood River, Illinois, Retzer attended Jefferson City Community College and the University of Central Missouri.

He was signed by the Cleveland Indians before the 1954 season, but played his entire major league career for the Senators after Washington acquired him in a September 1961 trade.

[1] In 1962, Retzer batted a career-best .285 with 97 hits and eight home runs, and was a serious candidate for Rookie of the Year honors.

[2] Retzer was also known for catching the first pitch of MLB's 100,000th game on September 6, 1963; the ball was presented to and preserved in the Baseball Hall of Fame.

He had a lifetime fielding percentage of .983 and threw out 48 of 126 baserunners making stolen base attempts, a rate of 38.1 percent.