Zachary Peter Gallen (born August 3, 1995 in Somerdale, NJ) is a professional baseball pitcher for the Arizona Diamondbacks of Major League Baseball (MLB). He made his MLB debut with the Miami Marlins in 2019.

Gallen was originally drafted by the St. Louis Cardinals in the 3rd round of the 2016 amateur draft. On December 14, 2017, he was traded to Miami alongside Sandy Alcantara, Daniel Castano and Magneuris Sierra in return for OF Marcell Ozuna in the fire sale that followed the Marlins' acquisition by Bruce Sherman and Derek Jeter.

On September 4, 2019, rookie pitcher Zac Gallen took a no-hitter into the 7th inning against the San Diego Padres, before surrendering a one-out single to Manny Machado. He had a 2-4 record in 12 starts entering the game in spite of an excellent ERA of 2.79, and once again was a victim of poor run support as the game was still scoreless when Machado reached base. He completed the inning with no further damage and then was the beneficiary of a four-run rally by his teammates in the bottom of the frame to end up a 4-1 winner, with three relievers completing his fine work.

He had started 2019 with the Miami Marlins, making his major league debut on June 20th, then was traded to the Arizona Diamondbacks on July 31st, in return for minor leaguer Jazz Chisholm. He finished the season at 3-6, 2.81 in 15 starts.

His sophomore major league season, 2020, was very similar to his first, as he was limited to 12 starts by the Coronavirus pandemic that cut down the season to just 60 games. He went 3-2, 2.75 as he led the Diamondbacks in innings (72.0) and strikeouts (82). In 2021, in his third start of the year on April 25th, he recorded his first career complete game and shutout when he hurled a one-hitter against the Atlanta Braves, winning 5-0. The game lasted only 7 innings as it was the first game of a doubleheader; in the second game, teammate Madison Bumgarner did even better, throwing an unofficial no-hitter in a 7-0 win.

In 2022, Zac took another step forward, and the DBack's Ace is considered one of the best in baseball. His ability to "pitch" without reliance on velocity and miss bats, and focus and competitiveness has led to major success at the big league level. In 2023, Zac was voted to the NL All-Star Team.

Zac's Italian Heritage was confirmed by Gianmarco Fararone, the FIBS Italian National Teams and Coaching Staff Coordinator. Zac is active on Twitter @zacgallen23

(excerpted from Baseball Almanac, BR Bullpen & Wikipedia)