Cavarretta joined the Cubs shortly after graduating from Lane Tech High School in 1934, moving two miles east on Addison Street to Wrigley Field. He played seven games for the Cubs in 1934 and was an everyday player in 1935, when he was still 18 years old for the first half of the season. Although he had very little power for a first baseman (he averaged less than five homers a year), Cavarretta was an excellent contact hitter who finished his career with a .293 average and more walks than strikeouts. He played 20 seasons for the Cubs and finished up with two for the White Sox.
Cavarretta earned the National League Most Valuable Player award in 1945 when he hit a league-leading .355 with 94 runs scored and 97 runs batted in. It was no fault of his that the Cubs lost the World Series to the Detroit Tigers in seven games. He homered and scored three runs in the Cubs’ 9-0 rout of American League MVP Hal Newhouser in Game 1, and he ended up batting .423 (highest on either team), with seven runs scored and five RBIs for the Series.
Cavarretta is the last Cub, so far, to hit a World Series home run. He was also the last in a long line of player-managers for the Cubs—which extended back to Cap Anson in 1879, and included Frank Chance, Rogers Hornsby, Charlie Grimm, and Gabby Hartnett. It was Cavarretta who, in 1953, wrote the name of Ernie Banks on the Cubs’ lineup card for the first time. The next year, he became the first manager ever to be fired in spring training, after he bluntly informed Cubs owner P.K. Wrigley that the club had no chance to contend.
"Phil hated to lose," Cubs outfielder Ralph Kiner said, "and he was very honest, and that was the reason he got fired." The Cubs finished seventh, 33 games off the pace, but being proven right did not get Cavarretta his job back.