Traynor was born in Framingham, Massachusetts. He received his nickame for a fondness for eating pie. He is generally considered to have been the greatest National League third baseman before the 1950s. Although he played in the era before the Gold Glove award was created, he was regarded by most baseball observers as the best-fielding third baseman ever until Brooks Robinson came along. He had a lifetime batting average of .320, and was struck out only 278 times in 7,559 career at bats. Playing his home games at Pittsburgh's spacious Forbes Field kept his home run total low, reaching a high of 12 in 1923. However, those long distances also aided him in hitting doubles and triples, and he had over 100 runs batted in (RBI) in a season seven times. He also managed the Pirates from 1934 to 1939.

In 1948, Traynor was selected to the Baseball Hall of Fame, being the initial third baseman to be chosen by the BBWAA. He died at age 72 in Pittsburgh, Pennsylvania, not long after the Pirates moved into Three Rivers Stadium and retired his uniform number 20. In 1999, he ranked Number 70 on The Sporting News' list of the 100 Greatest Baseball Players, and was nominated as a finalist for the Major League Baseball All-Century Team.