A native of
Clearbrook, Minnesota, Westrum was, in addition to his defensive prowess, a powerful right-handed hitter in his prime, although he had trouble making contact and hit for a low .217 career
batting average. He began his major league career as the Giants' reserve catcher, playing behind
Walker Cooper. When Cooper was traded in
1949, Westrum shared the catching duties with
Ray Mueller for the remainder of the season. Westrum was a key player for the Giants’ during the remarkable
pennant race in which the Giants, 13 games behind the
Brooklyn Dodgers on August 12, fought back to win 16 games in a row and finished the season tied with the Dodgers for first place. His two-run, eighth-inning home run against
Ralph Branca on August 13 snapped a 1–1 tie and gave the Giants a 3–1 victory over the Dodgers. Westrum contributed 20
home runs with 70
runs batted in, and led National League catchers in baserunners caught stealing. The two teams met in the
1951 National League tie-breaker series in which the Giants' season was climaxed by
Bobby Thomson's
''Shot Heard 'Round the World'', a three-run home run in the bottom of the ninth inning for a 5–4 win of the third and final playoff game. Afterwards, the Giants would lose to the
New York Yankees in the
1951 World Series. His
1952 season was plagued by injuries and he only managed to hit for a .220
batting average in 114 games, although he still managed to finish second to
Del Rice among catchers in assists. Westrum remained the Giants' starting catcher throughout the
1954 season, catching all four games in the
1954 World Series against the
Cleveland Indians. Injuries continued to take their toll, and by
1955,
Ray Katt had replaced him as the starting catcher. On September 29, 1957, manager
Bill Rigney started all the Giants who had been on the 1954 World Series team in the ballclub's final game at the Polo Grounds; Westrum caught during the 9–1 loss to Pittsburgh. When the Giants moved to San Francisco in , he was offered a role as a third-string catcher or as a coach. He decided to retire as a player at the age of 34, and accepted the coaching job. ==Career statistics==