The 38-year-old outclassed the previously unbeaten Swedish boxer to the delight of the M&S Bank Arena crowd, with the judges scoring the contest 99-91, 100-90 and 100-90 in favour of the British fighter.
Jonas (12-2-1) took control early on and despite going close to a knockout towards the end of the 10-round fight, she still did more than enough to clinch a 12th professional win.
After becoming unified champion of the super-welterweight division, she is now eyeing the WBA and IBF belts held by Hannah Ranking and Marie-Eve Dicaire respectively and could also drop back down to welterweight.
"There's two other belts to get and always the opportunity to become a two-weight or possibly three-weight (champion) because it is no secret I won't make super featherweight again," Jones told Sky Sports.
"I thought I lost a couple of rounds if I am honest but I can never really judge.
"I can hear (trainer) Joe (Gallagher) in the corner giving me hell all the way through, 'no, no, no, no' and I think 'oh god I am doing it wrong' but we came out with it."
The Toxteth-born boxer was fighting in Liverpool for the first time in three years.
Jonas beat Chris Namus in February at Manchester Arena to claim the vacant WBO title but insisted success over Berghult topped that night.
She added: "I honestly didn't think it could get any better than Manchester and tonight blew me away.
"I am so humbled by all the support, the love and the family and friends who support me every time. I always try and carry Liverpool with the best of my ability and do all the Scousers proud because we stick together, we love each other and we support one another."
It was a memorable day for the Jonas family after younger sister Nikita Parris scored for England in a 2-0 win away to Austria which clinched their place at next summer's World Cup.
Jonas' daughter Mela was also a spectator at home.
"Baby Mela, we've got another one. We've done it again," Jonas beamed.
Liverpool favourite Liam Smith also enjoyed success on the card but in bizarre fashion over Hassan Mwakinyo.
Light-middleweight champion Smith celebrated victory in the fourth round when Mwakinyo, who had appeared to hurt his ankle earlier in the contest, dropped to his knee and did so again in quick succession which saw referee Victor Loughlin wave off the fight.