Capra was a shortstop at Lane Technical College Prep High School in the Roscoe Village neighborhood on the Northside of Chicago.

Capra was a team co-captain his senior year, and led the Redbirds to the 1969 NCAA Division II Baseball Championship.

However, he was not so lucky in his third appearance: Facing the St. Louis Cardinals at Shea Stadium, Capra entered the game in the tenth inning, and retired only one of the seven batters he faced, Jorge Roque, who bunted Joe Torre to second after Torre had led off the inning with a single), on his way to allowing five runs and taking his first major league loss.

[3] Capra won his first major league start, over the San Diego Padres, on April 25, 1972;[4] however, he found himself back in the minors by the All-Star break.

His record as a reliever stood at 0–2, with one save (earned the evening Hank Aaron hit his record-breaking 715th home run, on April 8, 1974),[7] and a 3.06 ERA, when he replaced an injured Ron Reed, in the first inning, on May 15, against the Padres.

Capra's first game of the 1977 season also went poorly,[16] but he pitched effectively enough in his next four appearances (3 earned runs in 11.1 innings, while holding opposing batters to a .179 batting average), to be placed in the starting rotation when an injury to Andy Messersmith opened a spot.

Capra won his first game back in the bullpen,[17] for his first win since he beat the Mets on May 25, 1975 (two days shy of two years earlier).

[23] While attending Illinois State, Capra earned his degree in teaching, and taught ceramics at a Chicago high school during the off-seasons, while still a player.

[2] As a batter, Capra had only five runs batted in (RBI), in his playing career, the first coming on May 13, 1972, off Hall of Famer Juan Marichal, of the San Francisco Giants.