A graduate of Iona College, he entered pro baseball in 1950 in the White Sox system, and missed two seasons (1952–53) while serving in the military during the Korean War.

[1] Valentinetti made his MLB debut with the White Sox on June 20, 1954, and that was the only game he ever pitched for the team.

Valentinetti spent the entire 1956 season with the Cubs, working in 42 games, 40 in relief, and posting a 6–4 win–loss record, a 3.78 earned run average and one save.

The following season, however, he began to bounce around: between 1957 and 1960, he was a member of four MLB teams, five minor league clubs and seven different organizations.

[3] Following baseball, Valentinetti worked in construction and in city and state government positions in New York.