Sheehan, 27, penned a two-year contract with City after turning down the attentions of a number of other clubs to become Bantams boss Phil Parkinson's latest off-season capture.
The Irishman will officially join City on 1st July when his contract at Notts County expires.
Sheehan, who predominately features as a left back but can also easily ply his trade in central defence, played 44 times for County last season.
He also captained County during the campaign and won the club's Player of the Year award.
An expert at dead-ball situations, Sheehan took the vast majority of County's corners and free-kicks last season using his more favoured left foot.
His ability from free-kicks and corners means the defender has picked up a number of goals and assists over the years from set-piece situations.
He was also the Magpies' main penalty taker during the 2013/2014 campaign, with five of his seven goals last season coming from the spot.
Sheehan said: "When I spoke to the manager, he told me the plans he had for the club. He didn't really need to sell the place to be honest though, everyone knows what a big club Bradford is.
"I'm delighted to be part of the manager's plans here. I can't wait to get started now with pre-season and to meet all the boys."
Sheehan made over 100 appearances for County after moving to Meadow Lane back in 2011.
Before his time with County, Sheehan enjoyed a successful period with Swindon Town. Alongside new City captain Stephen Darby, Sheehan helped Swindon to the 2010 League 1 Play-Off Final.
Along with Darby and Gary Liddle, who he knows from his time at Notts County, Sheehan is also friends with fellow Irishman Mark Yeates.
As well as playing for Notts County and Swindon, Sheehan has featured for the likes of Leeds United and Leicester City during his eleven-year career.
After turning professional at Leicester, Sheehan spent five years with the Foxes before a move to Elland Road in 2008.
Sheehan had two years with City's West Yorkshire neighbours, helping them into the League 1 Play-Offs at the end of the 2007/08 season.
Including his time with Leeds, Sheehan has played the vast majority of his career at League 1 level.
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