The right-hander played in Major League Baseball for all or parts of 14 seasons between 1958 and 1975 for the Cincinnati Reds, Kansas City Athletics, Detroit Tigers, Cleveland Indians, Pittsburgh Pirates, Baltimore Orioles, St. Louis Cardinals and California Angels.

When Cincinnati's Frank Robinson hit a two-run home run in the ninth inning, Peña emerged as the winning hurler.

He signed with the Baltimore Orioles' organization for 1971 and was highly effective in minor league assignments (winning 33 games, losing eight, and posting a brilliant 1.14 earned run average in 317 innings pitched) through 1972.

He was mediocre in two trials for the Orioles, but, upon being acquired by the Cardinals on June 15, 1973, he became a key part of the Redbirds' bullpen, appearing in 84 games and notching nine wins and seven saves with a 2.36 ERA before being sent to his final MLB destination, the Angels, in September 1974.

The Angels released him the following May, but Peña continued pitching in the minors for the next two seasons, and made an abbreviated comeback at age 45 with the Miami Amigos in the 1979 Triple-A Inter-American League.