He played as a catcher in Major League Baseball from 1958 to 1965 for the San Francisco Giants, Washington Senators, Cincinnati Reds, and New York Yankees. As a rookie in 1958, Schmidt was selected to be on the National League team in the 1958 All-Star Game. On August 31, 1958, Schmidt hit a home run and had six runs batted in against future Baseball Hall of Fame member, Sandy Koufax, of the Los Angeles Dodgers, including a first-inning grand slam.
In 1961, he was traded to the Cincinnati Reds for catcher Editor Bailey.
Schmidt played as a reserve to regular catcher Jerry Zimmerman during the Reds" pennant-winning season of 1961, although he didn"t make the post-season roster when the Reds lost to the New York Yankees in the World Series. In 1962 he was traded along with Dave Stenhouse to the Washington Senators for Marty Keough and Johnny Klippstein.
Schmidt ended his career with the New York Yankees in 1965.