Berthiaume and Brenly were named on Thursday to replace Daron Sutton and Mark Grace. Grace's contract expired, and Sutton was not invited back despite having four seasons remaining on his contract.
The duo will be officially introduced on Nov. 5.
Brenly is very familiar to D-backs fans, given his history in both the broadcast booth and the dugout.
From 1998 to 2000, Brenly served as the team's TV analyst, paired with Thom Brennaman. Then, in 2001, he took over as the manager, and he led the D-backs to the 2001 World Series title. He was dismissed during the 2004 season; his .536 winning percentage is the highest in franchise history.
For the past eight seasons, Brenly has been broadcasting games for the Cubs, and when he was introduced at a game this past season, he received a loud ovation.
"That makes me feel good," Brenly said of his popularity with fans. "To be recognized and remembered for something that happened in an organization's past is special."
Although Brenly and his wife, Joan, have spent their summers in Chicago, they have maintained their home in the Phoenix area and stay there each offseason.
"We're just extremely excited," Brenly said. "The opportunity to come back home, logistically to live where we work and work where we live is awesome. For all the right reasons, it's time to come home."
"We are ecstatic to be bringing in such a dynamic broadcast duo like Bob and Steve," team president and CEO Derrick Hall said. "Not only are we able to reach back to our roots with someone who has played such a significant role in our franchise's history, but we truly feel that Bob is the best analyst in the game today. With Steve, we believe that his ability to connect with our fans and his tremendous work on the national stage over the last several years makes him the perfect addition to the booth."
The 47-year-old Berthiaume has spent the past 12 years working for ESPN, the last six as co-host of "Baseball Tonight."
He has also served as a play-by-play announcer on the network for Major League games as well as NCAA Baseball Super Regional coverage.
Berthiaume was recently in Arizona to meet with Hall, managing general partner Ken Kendrick, vice president of broadcasting Scott Geyer and executive vice president of business operations Cullen Maxey. He came away extremely impressed with the organization.
"It was clear that the D-backs are a first-class franchise and filled with tremendous people, and it's something I really want to be part of," Berthiaume said. "I'm thrilled to join the Diamondbacks and become [part of] one of the best organizations in sports. I'm really looking forward to interacting with D-backs fans through the broadcasts, at the ballpark and on Twitter."