He immediately made enemies left, right and centre, most notably of the Mitchells, and their feud is set to turn violent later this week.
Jonno met Phil and Ben when he went to The Vic for a drink, and ended up rubbing the father and son up the wrong way after making nasty comments about Pride.
He then went to meet Callum, Whitney and Stuart at Walford East, where Callum and Whit filled him in on their plans to get married.
Things seemed to be going well with their dad with Jonno even offering to buy Whitney her wedding dress, until the subject of Callum's career choices came up.
He told Whitney Callum use to be down the cadets as a child and the army was his dream.
When Callum said he couldn't go back due to medical reasons, Jonno called his son a "pansy" and suggested he left because the boys were picking on him.
It looks like Jonno won't be making many friends anytime soon as Ben antagonises him in the pub in Thursday night's episode (July 4 2019).
As Whitney uses Callum as a model for her Pride shirts, Stuart suggests spending some time with his brother but feeling uncomfortable in the shirts, Callum makes excuses leaving Stuart upset.
Later, Callum goes to The Vic with his dad for a drink but Ben starts subtly antagonising Jonno.
Mick warns Callum that his father is trouble.
Callum is then alarmed to notice his dad has followed Ben into the toilets.
Jonno confronts Ben in the bathroom, but Ben gets the upper hand leaving Jonno seething.
Realising he's not welcome, Jonno makes a hasty exit with Callum in tow.
Callum and Ben later have a heart to heart about what happened and as the pair open up about their pasts, they end up sharing another sneaky kiss...
However, what they don't realise is that Stuart has seen the whole thing!
Viewers know that although Callum is engaged to Whitney, he has been struggling with his sexuality.
During an argument with Ben, he figured out Callum's secret, and whilst at Callum and Whitney's flat-warming party, Ben opened up about losing Paul.
Not long after, Ben and Callum ended up kissing and having a one-night stand.
But Callum ended up proposing to Whitney and didn't tell her what happened between him and Ben.
EastEnders viewers are now convinced that Callum's fiancé Whitney is going to be killed off.
EastEnders is on Mondays and Fridays at 8pm and Tuesdays and Thursdays at 7.30pm.
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