Freese and pitcher Fernando Salas were sent to the Angels in exchange for outfielders Peter Bourjos and Randal Grichuk.
The acquisition of Freese solidifies the Angels' situation at third base. Freese, 30, is a career .286 hitter with 44 home runs and 237 runs batted in in five major-league seasons with the Cardinals.
He was an All-Star selection in 2012, the summer after he was selected the Most Valuable Player of both the NL Championship Series and the World Series.
Salas, 24, is 6-13 over 187 appearances the last four seasons. He picked up 24 saves in 2011 but has been used mostly in middle relief.
Bourjos has been in the majors for four years -- all with the Angeles. He hit .306 with 24 home runs and 89 RBI in that period. Grichuk, 22, hasn't played above AA ball but is seen as a strong prospect.