Pimblett stopped Leavitt with a rear naked choke early in round two to improve his record in the UFC to 3-0.
Leavitt enjoyed some success in round one, taking down Pimblett twice and attempting to control the fight on the floor.
But the British fighter was still able to land a series of significant strikes in the closing moments of the round.
He then overpowered Leavitt early in round two, securing a dominant position near the cage before locking in the rear naked choke.
In an emotional address to the crowd after the fight, Pimblett dedicated his victory to Lee-Joshua Hodgson, who tragically died last month at the age of four after battling a rare form of cancer.
He also paid tribute to a friend who had committed suicide in the days before the event.
Pimblett was in tears as he left the octagon with Liverpool's iconic anthem 'You’ll Never Walk Alone' playing in the arena.
Earlier in the evening, fellow Liverpudlian 'Meatball' Molly McCann extended her winning run in the UFC to three fights with another stunning knockout victory over Hannah Goldy.
McCann connected with a vicious spinning back elbow in the first round that rocked Goldy and forced referee Herb Dean to stop the contest after the British fighter continue to rain down punches on her opponent.
Victory for McCann and Pimblett was good news for Canadian rapper Drake, who won a bet of $3.7m (£3.1m) after backing the pair to win in London on Saturday.
But the evening would end in disappointment for the home fans when British fighter Tom Aspinall suffered a serious knee injury just seconds into his clash with Curtis Blaydes.
Aspinall aimed a kick at Blaydes but then collapsed to the floor in agony.
The Salford fighter was treated in the octagon for several minutes before eventually leaving with his leg in a brace, with Blaydes declared the winner by TKO.
Featured Image Credit: BT Sport
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