Pinellas County Sheriff Bob Gualtieri said at a news conference that Deputy Aaron Hull was fired Thursday after an internal review was done on the incident from last September.
"He knew what he should have done, but it seems like he got mad and couldn't control his anger," Gualtieri said.
In the video, which has no audio, Hull can be seen approaching 24-year-old inmate Taylor Schuessler, who uses a wheelchair, after he “verbally challenged” the deputy and other inmates, according to officials.
After kicking a chair, Hull marched over to Schuessler and placed his hand on the 24-year-old's neck before poking him multiple times.
“The actions provoked and escalated the inmate’s behavior,” officials said in a statement to FOX13.
Hull, a 12-year-veteran of the force, then used his left hand to grab Schuessler’s shirt and brought him closer when the 24-year-old spit in his face. The deputy reacted by striking Schuessler three time on the left side of his face as the argument continued before eventually calming down.
"There's no reason for it. It's not justified. It's flat-out wrong," Gualtieri said.
The sheriff said that deputies are given extensive de-escalation training in order to handle similar situations.
It was not the first time that Hull was disciplined for similar behavior. In 2015, Hull flipped a table as he approached an inmate, according to FOX13.
The inmate involved in the September incident, who has since been released, told authorities he liked Hull and didn't want to press any charges about the assault, WFLA reported.