"It's important that we have brought a player of Garath's quality through the door," said manager Brian McDermott after snapping up the free agent 25-year-old on a three-year deal.
McCleary blossomed late on in his career at Nottingham Forest. Given regular football by Steve Cotterill he repaid the City Ground boss by playing a key role in the Reds' run to safety in the Championship.
Most notably of course McCleary netted 4 goals in the 7-3 win at Leeds to catapult himself to the attention of the wider football world.
"Being a local boy as well, it's the stuff that dreams are made of," said the Oxford-born winger.
"I can't wait to pull the Reading shirt on and prove what I can do.
"After helping Forest stay up last season, It's a fantastic achievement for me to now come to a Premier League side, a club with such fantastic support. It's great to be here!"
Forest have also confirmed that Sean O'Driscoll is leaving the club to become the next manager of Crawley Town while next to follow McCleary out of the exit door is set to be Chris Gunter, subject of a £2m bid from Swansea City.