The 15-year veteran spent the past two seasons with the Boston Red Sox.
He'll be joining an Angels team that finished last in the AL West division last year with a 63-99 record, which was the fourth-worst record in all of baseball.
During his two years with Boston, Jansen put up 56 total saves in 64 opportunities with a 3.46 ERA and 114 strikeouts in 99.1 innings.
The power-throwing righty was part of the 2020 Los Angeles Dodgers team that won the World Series, an organization he spent the first 12 years of his career before going to the Atlanta Braves for a year ahead of his move to Boston.
Jansen is fourth on the all-time saves list. His 447 is just 32 short of surpassing Hall of Famer Lee Smith's 478.
The three closers ahead of Jansen, including Smith, are all members of the National Baseball Hall of Fame, leaving Jansen well on his way to joining others in baseball history once he hangs it up for good.