Pearce, a 22-year-old edge rusher who made a team-high 10.5 quarterback sacks last season as an NFL rookie, violated the league's personal conduct policy.
Police arrested Pearce near Miami in February after a disturbance involving girlfriend Rickea Jackson, a WNBA player.
Pearce was charged with three felonies - aggravated battery with a deadly weapon, fleeing and eluding police, and resisting an officer with violence - plus a misdemeanor stalking charge.
Pearce agreed to a six-month intervention program in April, with charges potentially dropped if he meets the program's conditions.
Pearce's suspension will begin on August 30, the deadline day for NFL clubs to reduce rosters to the regular-season limit of 53 players.
That will allow Pearce to continue to participate in Falcons pre-season activities.
He would be eligible for reinstatement on November 2nd ahead of the Falcons' November 8th game against Cincinnati at Madrid.