Gonzalez completed a physical examination in Milwaukee on Monday. The sides reached the deal last week.
Brewers general manager Doug Melvin says Gonzalez's experience and defense will make him a "a welcome addition to our infield."
The 34-year-old Gonzalez hit .241 with 15 home runs and 56 RBIs in 149 games with Atlanta last season. His .981 fielding percentage was fifth-best among major league shortstops.
Gonzalez is expected to replace last year's regular shortstop, Yuniesky Betancourt, who is a free agent.