Prentice was a good and durable forward, playing 1,378 games with five teams during 22 NHL seasons. He was a consistent scorer rather than a prolific one, finishing with nine 20-goal seasons but exceeding 30 goals just once. He was good enough to score 24 goals as a 23-year-old in 1955-56 and 26 as a 40-year-old in 1972-73.

Prentice played in five NHL All-Star Games, the last as a 37-year-old in 1970, and was named to the NHL Second All-Star Team in 1959-60 after finishing with NHL career highs in goals (32) and points (66).

After helping Guelph win the Memorial Cup in 1952, Prentice joined the rebuilding New York Rangers in 1952-53. He was a consistent contributor for 11 seasons in New York, though he was overshadowed by linemate Andy Bathgate, a future Hockey Hall of Famer. But the Rangers were mired in a stretch when they made the Stanley Cup Playoffs just once in eight seasons from 1958-66, and New York traded him to the Boston Bruins on Feb. 4, 1963.

Prentice scored 23 goals for Boston in 1963-64 and had 14 in 31 games in 1964-65 before a back injury sidelined him for the remainder of the season. The Bruins, who were also rebuilding, traded him to the Detroit Red Wings on Feb. 16, 1966.

The trade gave Prentice his first taste of success in the NHL playoffs. The Red Wings won their Semifinal series and went ahead 2-0 in the Cup Final against the Montreal Canadiens. However, Montreal won the next four games and the Cup. Prentice finished with 10 points (five goals, five assists) in 12 games.

Prentice played three more seasons with Detroit before being claimed by the Pittsburgh Penguins in the NHL Intraleague Draft on June 11, 1969. He scored 47 goals in 144 games in two seasons with Pittsburgh, then 46 in 144 games in his first two seasons with the Minnesota North Stars.

He played 24 games for the North Stars in 1973-74, his final season, and retired from the NHL with 860 points (391 goals, 469 assists), as well as 30 points (13 goals, 17 assists) in 54 playoff games.

After retiring, Prentice became the recreation director for Ayr, Ontario. He was 87 when he died Nov. 3, 2019.