The DCI Banks star had been accused of punching a man - who fell and suffered a brain injury - as he was making noise outside the star's North Tyneside home in the early hours in May 2021.
However, earlier this month he was found not guilty following a trial at Newcastle Crown Court, with the jury returning its verdict in less than two hours.
Tompkinson, 57, has now broken his silence in an interview on ITV's Lorraine.
Host Lorraine Kelly referred to the ordeal as a "nightmare", and the actor replied: "Yes a little bit. Not so much for me because I knew I hadn’t done anything wrong.”
“It could have been investigated a lot sooner and dealt with there and then”
After being cleared of GBH, @StephenTompki19 speaks exclusively to @reallorraine about what happened that night back in May 2021. #Lorraine pic.twitter.com/s3Q13x5Vyv
— Lorraine (@lorraine) May 19, 2023
Kelly admitted she had been worried about the Ballykissangel actor, saying: “You're back and you've put all of this behind you and I have to say you're looking a lot better because I was a wee bit worried about you.”
"Yes, well I am eating again, which is good," Tompkinson replied.
Kelly said the star just wanted to get back to work, and he agreed: "Absolutely."
Explaining what had happened during the incident in 2021, he said two men turned up outside, with one just in socks and underwear and the other also "dishevelled".
"They were the definition of drunk and disorderly," he said. "Several other people in the street had heard the commotion.”
He went on: "They were in a heck of a state, it turns out the chap was four times over the drink drive limit and so I called the police.
"They didn't seem to be horrible in any way...So I just thought if I asked them to move on and show them that I called the police. But, then they turned a bit nasty and turned on me.
"And I stopped one of them with my open palm from advancing any further because of the state he was in, he took a tumble and fell about eight feet away from me in that direction, smacking the back of his head and got a very serious brain injury, which, no joking matter, that had to be investigated."
He added: "Another neighbour had thought that… I had the phone in my hand and I had a dark blue dressing gown, she thought she’d seen a clenched fist. She was 125ft away and at a first floor window and saw me as the aggressor, which I wasn’t.”
Watch: Stephen Tompkinson leaves court after being cleared of grievous bodily harm