Des Hanrahan, Regional Business Manager, Bank of Ireland, presented Rob Kearney with the award at the renovated Donnybrook Stadium.
Kearney, who is equally comfortably at full-back or on the wing, was nominated based on his contribution to the December and January games.
That run of fixtures included Leinster's memorable wins over Castres Olympique, Connacht and Cardiff at the RDS and the away victory over Ulster at Ravenhill.
Reflecting on his award success, the Ireland international said: "Whenever you get any level of recognition from the supporters it gives you a boost and I'm delighted to receive this award.
"The supporters are who you play for. They're the people who have the well being of the team and the club to the forefront and they're the ones who stick by you through thick and thin.
"To get their backing for this award is fantastic. Overall I have been quite pleased with my own performances and the big thing for all of us is to try to maintain a high level of consistency over the course of the season."
Commenting on this weekend's Heineken Cup game against Edinburgh, Kearney added: "Edinburgh will be tough opponents again and they will be buoyed by their victory over Castres last weekend.
"But for us, this week it's all or nothing. It is critical that we finish these pool stages on a positive note and hopefully we can manage to do that with a strong support behind us at the RDS on Sunday."