In the original Series and other media Knock Out is a decepticon while in the movie continuity, Return of Convoy and eventualy Prime Knock Out is one of the Autobots.
NefariousLike Jolt, Knock Out was part of the team sent to counter Soundwave's attack on the power plant. He went along with Bumblebee and Landmine. He was also present at Galloway's rant about the damaged caused in the attack.
Later, he was on the NEST cargo plane transporting the captured Soundwave. He survived the crash caused by Buzzsaw and helped the other Autobots transport Soundwave by road. When Dirt Boss attacked the zoo where Soundwave is, Knock Out was attacked by Ratbat, who ripped out his front head light. Fortunately, he survived the assault, thanks to Bumblebee.
Later in Inyokern, California, Knock Out, Bumblebee, Landmine and the others meet up with Optimus Prime, who now has Soundwave secured, and is under interrogation.
He later takes part in the assault on the secret base in crater lake, Oregon. He survives the battle.
Knock Out is Decepticon's former doctor. Starscream called him to revive the Megatron. Knock Out's minion is Breakdown which Airachnid killed. Knock Out was at first A Bad Guy but in Predacons Rising Movie he became the member of Team Prime.