Macha had been the team's manager for two seasons, building a 157-167 record.
Milwaukee was 77-85 in 2010 and finished third in the National League Central.
Macha is 368-280 in his managerial career, which includes four seasons at Oakland.
"I tried to do what's right," Macha told mlb.com Monday. "I think if you're sitting there worrying about, 'What's this guy going to think?' it's not going to work. You come to the ballpark, study what you've got there, put out the best lineup and do what you think is the right thing. If you win enough games, then you're going to be there."
Macha took over the team prior to the 2009 season. Ned Yost had been fired with 12 games left in the 2008 season and was replaced on an interim basis by Dale Sveum.
The team's next leader with be the franchise's 18th manager.
The first was Joe Schultz, who led the club in its expansion season in 1969 when the team was the Seattle Pilots.
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