The misdemeanor charges stem from a January incident where he allegedly spit on a woman and forcibly grabbed her by the neck.
While McCain was facing up to six months in jail if convicted, the plea deal allows him to avoid jail time.
Instead, he will be required to attend 12 anger management classes as well as serve 10 days of community service.
The 26-year-old had spent time with the Miami Dolphins and New Orleans Saints to begin his career but truly made an impact with the Chargers last season, totaling five sacks while appearing in 15 games.
He signed with the Indianapolis Colts in the offseason, but he was told to stay away from the team once the charges were placed on him in June.
"We sat down with Chris and we just all agreed that this would be the best thing," head coach Frank Reich said, per Stephen Holder of the Indy Star.
McCain was placed on injured reserve for an undisclosed injury before being released in September.
He remains a free agent and is now able to sign with any team.