McCallum comes to The Hive London on a loan deal from Solihull Moors that will continue until the end of the season.
McCallum has scored 11 goals in all competitions so far this season for the Moors and gives Bees boss Darren Currie significant reinforcement in the attacking positions.
The big centre forward started his career as a youth product at West Ham United before featuring for the likes of Portsmouth, Aldershot, Leyton Orient and Eastleigh before making the switch to the Midlands last summer.
Our new number 15 is a proven goalscorer in the National League, scoring on 27 occasions in all competitions as Eastleigh went on to make the playoffs last season. The 26-year-old will be looking to have a similar impact when he pulls on an Amber shirt in this campaign.
Boss Darren Currie expressed his delight at getting the deal over the line.
He said “I’m really pleased, he was one of my top two targets in the summer. This has been bubbling away for the last few days and finally, it’s done!
“I have followed him for a couple of years now and I know what potentially he will bring to us, as well as his goals. He’s got a wide range of goals that he’ll get, he’s very good in the air, got good hold up play. He’ll be a huge player for us.
“I’m pleased to have Paul on board and I’m pleased for the fans to have a new signing coming in, so I’m delighted all round and I can’t wait to start working with him.”
The loan runs until 25th April but will automatically extend should Barnet reach the Vanarama National League play-offs at the end of the season.
McCallum won’t be eligible to play against the Moors when Barnet visit the SportNation.bet Stadium on Tuesday 11th February or if the two clubs meet in the play-offs.
Barnet also have an option to make the registration permanent at the end of the season.
McCallum has joined up with his fellow Bees and is immediately available for selection.