Ronnie Feeney, Regional Business Manager for Bank of Ireland, presented April's winner Jamie Heaslip with the award at Donnybrook.
On receiving the award, Heaslip said: "I'm delighted and honoured to receive this award from Bank of Ireland and I would like to thank all of the supporters who voted for me.
"Overall it was a mixed month for the team with some memorable performances at home and on the road.
"To be acknowledged by the Leinster supporters means a lot and I was delighted to play a small part in the wins.
"You really have to be on your toes at the moment because the level of competition is so high and there are a lot of the younger players such as Rhys (Ruddock), Dominic Ryan and Paul Ryan knocking on the door for selection.
"Last month we enjoyed some great wins over Clermont Auvergne in Europe and in the Magners League against Munster and the Ospreys and the key part of those individual successes was the collective squad effort.
"The senior and Academy players really stepped up the mark and our form in the league in that period leaves us in a decent position, even allowing for the disappointing defeats to Connacht - where we didn't perform to the standard that was required - and Glasgow where a largely Academy team really put it up to them in their own backyard."
He added: "We face another tough Scottish side in Edinburgh this weekend and games between the two teams are always keenly contested.
"They're a good all-round side with power up front and a number of dangerous backs who can open you up if you give them space.
"It's good that we have an opportunity to get back to action in front of a big crowd at the RDS and we're really fired up to get back to winning ways. It will be a tough challenge but one we'll relish.
"April was a big month for us on both fronts and now that we're out of Europe we have a massive period ahead with Edinburgh coming to the RDS on Sunday evening.
"It's vital that we bounce back from the disappointment in Toulouse and we all want to clinch a home semi-final spot, so motivation won't be an issue for the team."
Heaslip has delivered strong performances all season and will add the Bank of Ireland Leinster Player of the Month gong to other accolades which include several man-of-the-match awards.
The Kildare man played in four of Leinster's five April games. He was awarded the man-of-the-match honour in what was an intense tussle against provincial rivals Munster at the start of the month.
This was followed by the Heineken Cup clash against Clermont Auvergne in which Heaslip scored two tries, and a pace-injecting performance against the Ospreys.