Peterman was a three-year starter at third base for the Holy Cross baseball team from 1961-1963. During his junior year in 1962, he led the team to an overall record of 21-5, the District I championship and a trip to the College World Series. Peterman was named All-New England following his junior season, after posting a .362 batting average. As a senior in 1963, he led the Crusaders back to the College World Series for a second straight season, with the team winning another District I title and posting a 13-10 record. Peterman hit .291 during his senior campaign, while leading the team with 17 runs batted in. Following his graduation, he spent three years in the minor leagues after being drafted by the Pittsburgh Pirates. After his playing career, he later became the founder of the J. Peterman Company.