His deal is for three years, according to Maria I. Guardado of MLB.com.
"Over the past few weeks, our baseball operations personnel sat down with numerous highly qualified and impressive candidates for our managerial role. We are thankful to all of them for their time and effort throughout the process," Angels general manager Billy Eppler said in a statement, via Mark Feinsand of MLB.com.
"Ultimately, Brad's balance of connectivity, communication, and leadership skills as well as his understanding of evolving strategies and probabilistic approach to decision-making led us to him. We believe his knowledge, drive, and growth-mindset will allow him to integrate seamlessly with our players and staff and will be pivotal in advancing our culture and moving us toward our goals as an organization."
Ausmus spent last year in the Angels' front office after managing the Detroit Tigers from 2014-17.
During his four seasons with the Tigers, Ausmus amassed a 314-332 record and led the team to a first-place finish in the American League Central in 2014.
Detroit opted against extending his contract following the 2017 campaign.
Ausmus, 49, now replaces Mike Scioscia, who'd been the Angels' manager since 2000 and recently announced he wouldn't return in 2019.
The Angels finished fourth in the AL West in 2018 with an 80-82 record.