[5][6] He attended Keewatin High school in his hometown,[5] and was employed on the railroad and in iron ore mines during his teenage years, also dating Patricia Morris.

[8][9][10] As a senior in 1954, Cappelletti switched to T-quarterback and led Minnesota to a 7–2 record, missing the final game with an elbow injury,[11] a 27–0 loss at Wisconsin.

Cappelletti signed with the Winnipeg Blue Bombers of the CFL, but was traded to the Saskatchewan Roughriders, was later cut, and went back to the ORFU, leading the Sarnia Golden Bears (the team having changed its name in 1956) to the league championship.

[13] Cappelletti was out of professional football in 1959, back in Minnesota working as a bartender in his brother's lounge when he asked the Patriots for a tryout in the summer of 1960.

[14] With the launch of the American Football League (AFL) in 1960, he joined the Boston Patriots and was initially a kicker and defensive back.

[7][15][16] He switched to offense late in that season and teamed up with quarterback Babe Parilli to form a tandem nicknamed "Grand Opera Twins", due to their Italian surnames.

[14] He played with the Patriots all 11 years in Boston, from 1960 through the 1970 NFL merger season, and retired in late August 1971 at age 37;[1][18] he was the AFL's all-time leading scorer with 1,130 points (42 TDs, 176 FGs and 342 PATs) and among the AFL's top ten all-time receivers in yards and in receptions.

[21] During Cappelletti's pro career, he also returned punts and kickoffs, played defensive back and even had one pass completion for a touchdown.

After his retirement, he told an interviewer that during one game against the Kansas City Chiefs he remembered coach Hank Stram "...calling for screen passes and us yelling to our defense about what was coming.

[19][31] Cappelletti also served as color commentator for the Boston College Eagles during the famous "Hail Flutie" game in 1984.