Declan Grant struck Darren Munnelly after he came out of his house to ask Grant to stop shouting outside the home of his ex-girlfriend.
Mr Munnelly (46) had just returned home after taking his mother to the theatre for a retirement present when he was attacked at midnight on July 25, 2021.
He was later found with a serious head injury at a property in Carr Street, in the early hours of Sunday.
The injury had been caused by two punches to the head and a court heard how the second punch had caused Darren to fall to the ground and ultimately led to his death.
Mr Munnelly, whose family are originally from Doohoma, Co Mayo, had been out to the theatre with his mum earlier in the evening.
They then visited a bar in town, before ending the evening at his favourite local pub, the Queen in the West.
Lincoln Crown Court heard that Grant, who was drunk, had been involved in another altercation with his then girlfriend at a taxi queue just two hours earlier before he turned up at the home of his former girlfriend in Carr Lane.
When Mr Munnelly asked Grant to stop shouting the builder punched him twice in the face and left him lying on the ground.
Grant then fled into the home of his former girlfriend, while she went outside and tried to help Mr Munnelly.
Mr Munnelly, who worked as a community fundraiser, suffered facial injuries consistent with a substantial punch and further wounds to the back of his head after he collapsed to the floor.
Despite the efforts of neighbours to save him he suffered a fatal haemorrhage.
Grant was jailed for six years and six months after admitting manslaughter.
Detective Chief Inspector Richard Myszczyszyn, of EMSOU Major Crime, said: “The most heart-breaking aspect of this whole case is that if those punches had not been thrown, we would not be here. A family wouldn’t have lost their loved one. A community wouldn’t be mourning.”
He added: “Yet just two punches were thrown in anger, and they claimed Darren’s life.
“Each and every one of his family and friends have felt the profound impact that his death has caused.
“We hope that the conclusion of the court case today means that they are now able to draw a line under this tragedy and move forward remembering Darren in a positive way.”
Mr Munnelly’s son Sean Falkinder said that day in July had turned their lives upside down.
“Not a single minute has passed where the tragic passing of my dad hasn’t been the overriding thought on my mind with everything else becoming secondary,” he said.
“My dad was loved by all who had the pleasure of meeting him and his passing has affected far more afield than just our immediate family and friends.”
In a direct tribute to his father he added: “Father and son, the best of friends, I thank you for everything you taught me about becoming a man. I hope to keep making you proud every single day.
“We may never get another gig, duet or frame together, but we will always have our memories. Remembering you always, Sean.”
Mr Munnelly also leaves teenage son Jack, who said his dad was “like my best mate, I told him loads of stuff”.
“I was with him every weekend and we did everything together,” Jack said. “Since he’s been gone I don’t know what words to use.”
His parents, Billy and Karen remembered a son invested in his local community, who spent lockdown developing a love of cooking and provided meals for people in need.
In a joint tribute, they said: “Darren was the most perfect son you could have. He was happy go lucky, and just lived in the moment. He was such a tremendously popular person loved by the community, someone who was very kind to other people. He will be missed and loved greatly by all of us.”
His big sister Cheryl said Darren was “a very special brother to me; he was one in a million.
“The friendship and bond between us growing up was unique. He had the best personality with the biggest heart.
“We spent 46 Christmas days together as a family. I will remember our laughs together, that cheeky grin and those crystal blue eyes and all the wonderful memories of my loving, funny, kind brother who meant the world to me.”
Part of Lincolnshire Police’s ongoing work to reduce violent crime involves working with registered charity OnePunchUK to raise awareness of the devastation that a one punch assault can have on the victim and their families.