The 24-year-old marked a significant step up in quality with a dominant and brutal performance to demolish opponent Sean Davies.
It could easily have been over inside the first round when the unbeaten Doncaster fighter twice had Davies down with rights.
Another big right had Davies down again in the third before a vicious left hook brought the inevitable end in the fourth, seeing Mould collect his first professional title in his 12th fight.
It had been the first time Mould had fought an opponent with a genuine winning record and he passed the test with flying colours.
Victory brought the English title later than planned however, with Mould denied a shot earlier in the year due to a anomolous brain scan which was belatedly cleared.
His attention now is likely to quickly turn to the British crown, currently held by Ryan Walsh who is set to defend against Lewis Paulin on Friday.
It has been a good week for Mould’s camp, with trainer Sean O’Hagan guiding his son Josh Warrington to a narrow victory over Kid Galahad for a successful defence of his IBF featherwright title.
Earlier in the night, Chapletown’s James Rayworth marked his professional debut with a 39-37 points victory over Zygimantas Butkevicius. After a fiery opening round in which the two men had to be separated at the final bell, Rayworth began to take control off the jab and was a comfortable winner.
Another debutant was Doncaster’s Taylor Watkins who edged a tight points decision 39-38 against Luke Middleton.
Elsewhere, Sheffield trained Lee McGregor made a successful defence of his Commonwealth bantamweight title against Scott Allan in Glasgow.
McGregor – who trains at the Steel City gym alongside Dalton Smith and the Edwards brothers – stopped Allan in the eighth round.