The league announced Wednesday that Jackson has been suspended indefinitely without pay.
Jackson was also suspended indefinitely in August 2012. He was given what was expected to be his final chance to play again when the NFL reinstated him in May.
The Redskins re-signed him, and he said during a spring practice that this time would be different in part because of the "humbling experience" of having to work in a warehouse during his suspension.
The 28-year-old Jackson was suspended twice while playing for the Tampa Bay Buccaneers: four games in 2009 and for 12 months starting in September 2010. He first signed with the Redskins in April 2012.