Hamilton was activated before Tuesday night's game at Houston. He was playing left field and batting cleanup.
The former AL MVP has been out since tearing a ligament in his left thumb sliding headfirst into first base on April 8. He played three rehabilitation games for Triple-A Salt Lake.
Hamilton hit .444 with two homers and six RBIs in eight games for the Angels this season before getting hurt.
The Angels optioned right-hander Jarrett Grube to Salt Lake on Sunday to make room on the roster for Hamilton. They also selected the contract of right-hander Cam Bedrosian from Double-A Arkansas and optioned right-hander Michael Kohn to Salt Lake.
Bedrosian, a 22-year-old reliever, has a 1.47 ERA in 17 games this season for Arkansas.