Crews, who plays Hale Caesar in the Expendables franchise, will be a bodyguard and unofficial life coach for Jeff Daniels's character Will McAvoy, according to Entertainment Weekly.
The ex-LA Rams, San Diego Chargers, Washington Redskins and Philadelphia Eagles sports star will first appear in the show's sixth episode on July 29.
He will also return for the second Expendables movie, which premieres in the US on August 17.
The Newsroom was picked up for a second season by HBO earlier this week, despite a mixed response from critics. The show premieres in the UK on Tuesday, July 10 on Sky Atlantic.
Watch Terry Crews's classic Old Spice commercials below: