The 39-year-old former Ireland international will begin his new job in March, heading up Quins’ existing coaching staff of John Kingston, Colin Osborne and Tony Diprose.
Head coach Kingston recently agreed a new contract, but Diprose was thought to be among the rugby director contenders alongside British and Irish Lions coach Ian McGeechan and ex-Scotland supremo Frank Hadden.
Quins though, have turned to one-time London Irish rugby director and player O’Shea, who won 35 Test caps between 1993 and 2000.
O’Shea, currently national director at the English Institute of Sport (EIS), will fill the vacancy created by Dean Richards’ resignation.
Former England number eight Richards quit following his role in the ‘Bloodgate’ scandal which subsequently saw him get a three-year worldwide coaching ban.
Apart from Richards’ suspension, there were also bans for ex-Quins physiotherapist Stephen Brennan and wing Tom Williams, who returned to playing action last month.
The club additionally landed a sizeable fine imposed by European Rugby Cup Limited, although they avoided expulsion from this season’s Heineken Cup, a punishment many people had thought likely.
Quins chief executive Mark Evans said: “After a thorough search, the board are delighted to have secured Conor’s services. He combines international playing experience with a proven managerial track record in rugby and elsewhere.
“We are very confident he has the skill-set we were looking for and will dovetail extremely well with our current playing management staff.”
The EIS announced the capture of O’Shea in March 2008, a role he took up after leaving the Rugby Football Union, where he was employed as national academy director.
“I have thoroughly enjoyed my time at the EIS and it is a shame that I will be moving on at such an exciting and challenging time for the organisation and for sport in this country,” he said.
“But plain and simply, my passion lies with rugby and my desire to influence at the sharp end of the game has never diminished. So when approached by Harlequins, a club with an exciting squad, a committed and talented group of coaches and support staff and a stable business model to underpin long-term success, I knew it was a challenge I had to take on.”
O’Shea will remain in his post at the EIS for another three months but should be on board at Quins in time for a possible Guinness Premiership play-off push.
While Quins face an early exit from this season’s Heineken Cup having lost their first three pool games, their Premiership form is better and they currently lie five points off a top-four place.
With Kingston at the helm, Quins have recovered steadily from the ‘Bloodgate’ saga and strung together an impressive Premiership run that has seen them lose once in their last seven matches.