[2] On 2 February 2009, Bangor's board announced that they would not be able to renew their domestic licence due to financial difficulties, and thereby would not compete in this season's premiership.
After a two-legged series against 2008–09 Championship runners-up Donegal Celtic, which ended in an aggregated 2–2 tie, Dungannon eventually retained their Premiership status on away goals.
Promoted from the Championship were 2008–09 champions Portadown, which marked their return to the highest football league of Northern Ireland after a one-year hiatus.
The promotion/relegation play-off was slightly altered this season because Donegal Celtic, runners-up of the 2009–10 IFA Championship, were the only IFA Championship club to hold the Domestic Club Licence required to participate in the Premiership.
The second leg stayed goalless until the 85th minute, when Stephen McAlorum scored for Donegal Celtic, to relegate Institute to the 2010–11 IFA Championship.