"This is an emotional day for me," said Garagiola. "The Diamondbacks franchise has meant so much to me and my family, and I take great pride in all that we have accomplished.
"In a short and memorable amount of time, we have built an organization from scratch, and brought the best fans in the game a World Championship," he added. "I leave knowing that there are many more great days ahead for this franchise."
Garagiola will begin with Major League Baseball on Aug. 15 and will report to newly appointed Executive Vice President of Baseball Operations Jimmie Lee Solomon, who previously held Garagiola's new post.
In seven seasons, Garagiola helped the team reach three National League West titles, one National League Championship, and a World Series Championship.