[1] Born in Newark, New Jersey, he threw and batted right-handed,[2] stood 5 feet 11 inches (1.80 m) tall and weighed 185 pounds (84 kg).

Walsh's professional career began in 1941 and was interrupted by two years of United States Army[3] service during World War II.

He worked in only 15 total games during his first three trials with the Pirates before sticking with Pittsburgh for the full 1950 and 1951 seasons.

For much of Walsh's tenure, the Pirates wallowed at the bottom of the National League standings, and in his 89 total MLB games, he posted a 4–10 won–lost record and 5.88 earned run average, allowing 201 hits and 111 bases on balls in 193 innings pitched, with 91 strikeouts.

In 12 starting assignments, Walsh notched one complete game, which was also his only shutout; it came on August 18, 1949, a three-hitter against the Chicago Cubs at Forbes Field.