An army corporal based at Dale Barracks assaulted his girlfriend’s roommate, who was also her ex-boyfriend.
Gary King, 30, punched Damian Cjazka multiple times at the house he shared with Ilona Sokolowska on Conway Road, Chester.
Mr Cjazka suffered injuries to his face and back as a result of the attack.
King was spared a suspended sentence, which would have seen him demoted, because of his ‘exemplary’ army record.
He was fined £450 and must pay £300 compensation to his victim at Chester Magistrates Court.
Presiding magistrate Stuart Clarke said: “You know it’s unacceptable to behave in this way, but because of your guilty plea and exemplary service we are going to settle with a fine.
“Be careful in the future, you don’t want to lose a career you have clearly given years of your life to.”
King, from Nottingham, went round to his girlfriend’s house on July 31.
Mr Czajka claimed to hear banging up the stairs before the 30-year-old burst into his bedroom and attacked him unprovoked.
He said when he tried to get up he was pushed back down and punched again in the face.
King claimed Mr Czajka had his hands around Ms Sokolowska’s neck when he arrived and admitted hitting him twice before shoving him to the floor.
Howard Jones, defending, said: “Throughout the evening he had been receiving texts from his partner that she had been arguing with her roommate and she was scared.
“That’s what resulted in Mr King going round to the address.”
But in her own interview with police, Ms Sokolowksa said the hands were on her shoulders, she was not being choked and they were ‘just shouting in each other’s faces’.
Carolyn Viviani, prosecuting, said the defendant did not see any of the argument.
Mr Czajka was taken to the Countess of Chester Hospital for treatment as a result of the injuries he suffered.
King, who has been in the army for nine years, must also pay £85 prosecution costs and a £45 victim surcharge.