He was capped at senior level by Australia against Ireland, while also fitting in a spell in the Super League and a couple of seasons in Japan.
The 42-year-old coached in Japan before his return to Australia where he worked for four years with the Brumbies during which time he also coached Australia 'A' before joining Leicester Tigers.
He joined the Tigers coaching team in early 2009, with Tigers picking up the Premiership trophy at Twickenham and reaching a fifth Heineken Cup final where they lost to Leinster at Murrayfield.
After retaining the Premiership title in May 2010, O'Connor became Leicester's head coach in July of that year and led them to successive runners-up positions in the Premiership and in 2012 the English side won the LV= Cup.
The Australian will link up with Leinster Rugby on July 1.
Commenting on the appointment, Leinster Chief Executive Mick Dawson said: "We're delighted that Matt has agreed to become head coach and we believe that he will be carry on the fine work which has been done over the course of the last eight years.
"Matt joins Leinster with an impressive pedigree under his belt at club level with the Brumbies - who were provincial champions in 2006 - and Leicester Tigers - who have boasted the league's best defensive record (in 2009/10) and most tries scored (between 2008 and 2013) - during his time on their coaching team.
"We were impressed by Matt's vision for Leinster Rugby and speaking to him it is clear that he is excited about the opportunity. We look forward to working with him over the coming years.
"Obviously we're still in contention for three trophies, the Amlin Challenge Cup, PRO12 and British & Irish Cup, and all of our focus will be on trying to end the season on a high in all three competitions."
Matt O'Connor said: "I am delighted to join Leinster. The playing staff, coaching team and facilities are first class and I have been hugely encouraged by the hunger within the province to push on despite enjoying an unprecedented period of success on the field in recent years.
"I look forward to working with the province's established and burgeoning talent from the renowned Leinster Academy and I am also pleased to work with the current coaching team who have played such a key part in the province's success over the last four years.
"At this time my focus remains with Leicester, but I would like to thank the Leinster Board for this vote of confidence and my family and I are hugely excited about starting this new chapter in our lives."