Bloom, whose title will be chief baseball officer, succeeds Dave Dombrowski, whom the Red Sox fired as president of baseball operations in September, less than a year after winning the 2018 World Series. Boston failed to make the playoffs this season, finishing 84-78, 19 games behind the American League East champion New York Yankees.
"It is an incredible honor to have the opportunity to lead the Red Sox baseball operations department," Bloom said in a statement. "The talent and dedication of our staff, and the culture that they represent, are remarkable. I'm excited to work with them to take this organization to new heights. ... The bond between the Red Sox and our fans is second to none, and my family and I are eager to make New England our home."
Bloom, 36, had spent 15 years with the Rays in capacities including minor league operations, player development, contract negotiations, salary arbitration and international scouting. He has operated in a front office unlike Boston's in that the Rays have a low budget and remain competitive. This season, they had the lowest payroll on Opening Day at $49.08 million, and the Red Sox had the highest at $187.23 million.
"We believe Chaim is exactly the right person to lead the Boston Red Sox baseball operation based on a number of attributes we sought in this process," Red Sox principal owner John Henry said. "We had done exhaustive work narrowing down candidates. That work led us to Chaim, who was the first executive invited to Boston for an interview. He made a strong impression on all of us and validated our initial research that he was the one to lead our baseball operation."
Late in September, Henry and owner Tom Werner said at a news conference that they intended to make major cuts to the payroll to get under the luxury tax threshold next season. They said they fired Dombrowski because of differing opinions on how to build for the future.
It's a crucial offseason for the Red Sox, who need to decide what to do about 2018 AL MVP Mookie Betts, who will be a free agent after next season; slugger J.D. Martinez, who can opt out of his $23.75 million deal for 2020 five days after the World Series; and other players on expiring contracts.
"This is a great day for the Red Sox," president and CEO Sam Kennedy said. "It became clear during the search process why Chaim has become one of the most respected and talented executives in the game. I am looking forward to working closely with him and his team to bring our fans the fifth World Series championship under this ownership group."
Bloom is a Philadelphia native and attended Yale, graduating in 2004 with a bachelor's degree in classics.