The 22-year-old lost his life when he crashed in the Supersport race on his TJR Kawasaki.
He was making his debut at the event, which was the first Irish national road race in the Republic of Ireland in almost three years after every meeting in 2020 and 2021 was cancelled due to Covid-19 restrictions.
The event was abandoned after the fatal accident, which Irish police said happened at approximately 1.30pm.
Earlier, Jack had finished as the runner-up in the Junior Support race and claimed 10th in the Senior Support class.
A bright prospect, he secured his first Irish road racing victory at the Cookstown 100 in Co Tyrone in April, winning the Senior Support race.
The fatal incident sent shockwaves throughout the road racing community.
Jack’s father, Tommy, said he had been left “totally broken” by the tragedy.
“I’m totally broken. I can’t cope with this,” he wrote in a heart-wrenching tribute on social media.
“Always in my heart forever son, love you forever.”
The tragic racer’s brother Robbie also took to Facebook to pay an emotional tribute, writing: “As some may have heard, our wee rocket has gained his angel wings at Kells Road Races doing what he loved.
“I am sure that big grin was on full display. I honestly have no words.
“Ride high my brother, I will always love you.”
A statement from Gardaí said Jack was pronounced dead at the scene before being taken to Navan Hospital.
“Gardaí and emergency services have attended the scene of a single vehicle collision at a closed racing circuit in Crossakiel Co. Meath, this afternoon, Sunday, 17th June 2022,” the statement said.
“The collision occurred at approximately 1:30pm and involved a motorcyclist.
“The motorcyclist, a man aged in his early 20s, was pronounced dead at the scene. His body has been removed to Navan Hospital.”
Fellow Limavady man Mervyn Whyte paid tribute to the Northern Ireland rider, describing him as “an up and coming star”.
“It’s very sad news about Jack Oliver, an up and coming star from my hometown,” said the North West 200 race chief.
Prior to the red flag stoppage, Skerries man Michael Sweeney won the Open Superbike race on the MJR BMW from Mullingar’s Thomas Maxwell.
Wexford’s Graham Kennedy completed the top three ahead of Ballymoney rider Darryl Tweed, who was riding a 600 Honda for the Wilson Craig Racing Team.
The next Irish road race is due to take place at Skerries from July 2-3.
Irish road racing stalwart Davy Morgan was escorted to his hometown in Saintfield by a large turnout of bikers yesterday as his body returned home from the Isle of Man.
The popular Co Down rider was killed in a crash in the first Supersport race at the TT almost two weeks ago.
His funeral will be held tomorrow at Saintfield Presbyterian Church. A time has still to be confirmed.
A total of five competitors died at this year’s TT, the highest number of fatalities since 1989.