The match at the Staples Center in Los Angeles lasted the full six rounds, with two of the three judges giving the victory to KSI.
The rematch came after the initial fight between the two in August last year was declared a majority draw, meaning that while KSI remained his belt, no overall winner was announced.
The pair exchanged punches in their first professional fight with lighter gloves and no headguards – with world champions Devin Haney and Billy Joe Saunders on the event’s undercard.
Other YouTubers also fought during the event, with Joshua Brueckner of the channel Jatie Vlogs proposing to his girlfriend Katie after winning in his professional debut.
The match began with some early aggression from KSI, before Logan delivered a series of uppercuts in the fourth round, who was deducted two points for punching KSI while he was down.
The final two rounds were a rush from both fighters to deliver a knockout, but neither were successful.
Commenting on his second fight against Logan compared to his initial match, KSI said: “KSI last time was scared. I was scared to fight. This time I just went in.
“Your boy has done it, I am victorious,” he said.
He also thanked his team after the match, including his trainer, Viddal Riley.
Meanwhile, Logan Paul said that KSI was one of the toughest people he knows, adding that he wished him the best.
AnEsonGib, real name Ali, remains undefeated as an amateur boxer, while Jake won his fight against KSI’s brother Deji in Manchester last year.
When asked by Sky Sports about a potential match against Paul, Ali responded by saying “it’s been nearly a year and Jake Paul is ducking me”, calling on boxing promoter Eddie Hearn to arrange the match.
The event also caught the attention of celebrities, with singer Justin Bieber backing Logan Paul and rapper Wiz Khalifa supporting KSI.
At the end of the match, the pair shook hands, with the pair thanking each other for a good fight.
KSI ruled out a third professional fight with Logan, saying “it is done”.