Budding actor Nashon Esbrand was hunted down by youths on bicycles near his parents' home in Islington, north London, and stabbed with a Rambo knife.
As he lay dying in the street, the "smiley and well-mannered" 27-year-old's last words were: "Don't let my mother see me like this."
Cally Gang member Jack Stevens, 19, who co-ordinated the attack, fled to Spain but was extradited back to Britain.
He was found guilty of the murder following a trial at the Old Bailey, and judge Anuja Dhir QC jailed him for life with a minimum term of 23 years.
She said: "It was a co-ordinated, brazen attack, the final part of which was quick and ruthless."
She told Stevens: "You were the leader of the group that attacked and killed Nashon Esbrand.
"You bore a grudge against him and Nashon was aware of it. He had spoken to the police, his family and also his doctor about it."
The murder came after a "campaign of harassment and violence by local gangs" against the victim, the judge said.
Following his conviction, Stevens showed a "chilling lack of remorse".
The judge told him: "Without you this senseless murder would not have taken place. You brought the team together."
The court had heard that Mr Esbrand had clashed with members of the north London Cally Gang or Cally Boyz in the past - and had warned police that his life was in danger.
On the evening of August 24 2017, he visited his parents' home in Islington with his girlfriend and his two-week-old daughter.
After dropping his girlfriend and baby back home, he then set off to return to his parents' house to pick up his car.
En route, he was spotted by Stevens and Dillon Zambon, the court heard.
Stevens called for reinforcements and Mr Esbrand was chased by youths on bicycles through the back streets.
He was cornered in Mitchison Road and attacked just 15 minutes after saying goodbye to his girlfriend and daughter.
As he ran for his life, he phoned his father Desmond, who rushed out to find him.
His son had been fatally stabbed in the legs and died in hospital in the early hours of the next day.
The attacker, now aged 17, admitted murder and was detained for a minimum of 12 years.
Zambon, 21, and Jhon Berhane, 19, were found guilty following a trial last March and were locked up for at least 21 years.
The court heard moving victim impact statements from Mr Esbrand's "heartbroken" parents and siblings, who sat through two trials.
Mother-of-five Princess Barton said the death of her youngest child was her "worst nightmare".
She said: "This stabbing epidemic is rife. This killing must stop."
Desmond Esbrand said he felt "guilt" at not being able to protect his son, as the last person he spoke to that day.
He said: "Not only do I feel like I failed because I believe that every parent from the day their child is born has a duty to protect and look after them. Due to the fact my son has been murdered, my life has changed too."
His son's last words as he lay mortally injured were: "Don't let my mother see me like this."
In a note to his newborn daughter, Mr Esbrand wrote: "You are the most beautiful person I have ever seen. I will protect you and watch over you like my mother and father did me. You are my daughter and my world, my conscience and the apple of my eye."
Chantelle Esbrand described her brother as "very smiley, well-mannered, respectful and he loved life".
She said: "He had just become a father for the first time. He was ecstatic. His life had just begun."
Mark Barton described his brother's murder as "barbaric" and "inexcusable".
He had ambitions to achieve success as an actor and wanted to volunteer his spare time to support young people, Mr Barton said.
The court was told that Stevens had previous convictions including one for causing the death of a teenager when he was aged just 15.
He had been speeding on a stolen moped when he crashed, leaving pillion passenger Joe Walker, 18, a promising footballer, to die at the scene.
Stevens pleaded guilty to causing death by careless driving in 2015 and was sentenced to a detention and training order at Blackfriars Crown Court.
Michael Ivers QC, mitigating, said Stevens' mother felt the moped death and the death of another friend had had a "negative" impact on him.
Stevens waved to the public gallery as he was sent down from the dock.