Hazen replaces Dave Stewart, who fired along with manager Chip Hale a day after the regular season ended.
''We feel very strongly that we have found the ideal candidate to lead our baseball operations,'' Diamondbacks managing general partner Ken Kendrick said Sunday in a statement. ''Mike's reputation throughout the game is impeccable, and his championship experience gives us great confidence in naming him to this position.''
The 40-year-old Hazen served as senior vice president and GM of the Red Sox last season after four years as the team's assistant GM. He spent 11 seasons working in his hometown of Boston, working in every aspect of baseball operations.
The Red Sox won the World Series twice and reached the postseason five times during Hazen's tenure. Boston was swept in three games by Cleveland in the AL Division Series this year.
Hazen becomes an executive vice president with the Diamondbacks, along with their GM.
''Mike's background is the perfect balance of scouting, player development and analytics, which will all play an important role going forward,'' Diamondbacks President and CEO Derrick Hall said. ''He's a natural leader, who we feel fortunate to have been able to hire, and we welcome him and his family to Arizona.''
Hazen previously spent five seasons with the Cleveland Indians, working in scouting and player development. He graduated from Princeton and played two seasons in the minor leagues.
The Diamondbacks made a leadership change after failing to reach the playoffs five straight seasons. Arizona has not had a winning season since taking the NL West title in 2011 and went 69-93 in 2016.
''I'm extremely grateful for this incredible opportunity to help the D-backs reach the next level,'' Hazen said. ''This is a franchise that has experienced a lot of success both on and off the field in less than two decades of existence, and I'm looking forward to working with Ken and Derrick to help bring back a tradition of winning to Arizona.''
In a statement, Boston President of Baseball Operations Dave Dombrowski said ''while this is certainly a significant loss for the Red Sox organization, we are extremely happy for Mike and his family as they begin this new opportunity in Arizona.''
''As one of the most respected young baseball executives in the game, Mike is more than deserving of this position,'' he said.