The 27-year-old back rower played for Ballymena in All-Ireland League Division 1 before moving to England and has represented Ireland at Under-21 and Sevens level.
There were a couple of factors involved in McComish's decision to return to Ulster. He said: "Being from here, I want to play for my home province.
"It's also very much about winning trophies - Ulster came close last season and I think we can do even better this season and win some silverware. For me, this season will also be about trying to break into the side."
He was in Majorca with former Connacht team-mate Mike McCarthy for 10 days' holiday, but he had little time to relax on his return as he went straight back into pre-season training with Ulster.
McComish added: "My sole focus now is to impress the coaches in training. So far we have been doing full body weights, with speed sessions and conditioning games. Pre-season has been enjoyable but very tough."
When he gets a break from training, he regularly visits the coast for a spot of fishing and to get his 'head showered.' But with the Ulster squad currently 'enjoying' full days of training, it may be some time before he can get the fishing rod out again.
Meanwhile, Kukri's latest Ulster Rugby designs, including their colourful supporters' jersey, are now available to buy across Ireland.
The range is expected to fly out of shops if pre-orders are anything to go by, so make sure you are not left empty handed and get down to your nearest store.
To view the range of Ulster kit and merchandise or to make an online purchase, please click here.