Blount exited the arena before the end of the match as the Steelers (7-4) went on to win 27-24 against the Tennessee Titans at LP Field in Nashville.
The 27-year-old - recruited from the New England Patriots on a two-year deal before the start of the NFL season - was reportedly unhappy at receiving zero carries in the game.
Blount's actions on the road were the final straw for the Steelers, who announced his departure on Tuesday.
"We believe the decision to release LeGarrette is in the best interest of the organisation and wish him the best of luck," Steelers head coach Mike Tomlin said in a statement.
Pittsburgh centre Maurkice Pouncey was less than impressed with Blount when quizzed by the media on Tuesday.
"If you don't want to be here, don't be here," Pouncey said. "He had a decision to make as a man, and he made it. You know the consequences."
Safety Mike Mitchell, however, attempted to defend his former team-mate.
"I actually know him, and a lot of people don't know him. He is not a selfish guy at all," Mitchell said.
"He is a competitive guy who wants to be on the field, wants to win games, wants to help us win games. It's a bad perception I think he gets a lot of times, but he has to be smarter in that situation."
Blount rushed for 266 yards and two touchdowns in 11 games for the Steelers since his arrival in March.