Bachmann announced her bid during a GOP presidential debate in New Hampshire. The third-term Minnesota congresswoman is the first woman to enter the 2012 race.
Despite having low seniority and few policy accomplishments, Bachmann has risen to prominence in Washington in part by her frequent TV appearances and willingness to attack President Barack Obama.
Her popularity with tea party activists and her credentials as a social conservative make her a credible threat to other candidates courting conservatives.
Bachmann has been considering a run over the past few months, visiting early primary states, raising money and railing against Obama.
"Our country needs a leader who understands the hardships that people across America have been facing over the past few years, and who will do what it takes to renew the American dream. We must become a strong and proud America again, and I see clearly a better path to a brighter future," Bachmann said in a statement issued through her new campaign.
Bachmann is known for unyielding stances, biting commentary and high-profile gaffes. She once accused Obama of running a "gangster government."
The Associated Press contributed to this report.