He played an important role in the Tigers' progress in all four competitions in the 2006/07 season as they achieved a Guinness Premiership and EDF Energy Cup double and also reached the finals of both the Heineken Cup and the Guinness 'A' League.
He made 15 appearances for the Tigers senior side during that campaign, scoring 100 points including two tries.
Having captained Ireland at the Sevens Rugby World Cup in Hong Kong during 2005, Humphreys made his Ireland 'A' debut during 2007 and he was also selected for the Churchill Cup played later that summer.
The brother of current Ulster out-half David Humphreys, the 25-year-old Ian has also represented Ireland at Under-19 and Under-21 level. He was capped by the Barbarians against the Combined Services in 2004 and the Royal Navy in 2006.
Commenting on his move home, Humphreys said: "I am really pleased to be signing for Ulster. Everyone who grows up in Ulster wants to play for Ulster and it is something that I have always wanted to do.
"When the chance came along I took it and I am really looking forward to it. It will be great playing alongside a lot of guys that I have grown up with and played alongside at various levels. I went to school with Matt (McCullough) and Bryan (Young) and Rory (Best) is one of my best mates."
When asked if elder brother David had been offering him any advice, Ian added: "David has always been there for me. I have talked to him about things and he told me that everything is going well under Matt Williams and he likes the way things are being run. He is there for advice but would never force his opinions."
With David retiring next month, Ian will take up the 'Humphs' baton by linking up with the Ulster squad for pre-season training in June.