Waldrom received the award for December after being selected by a panel of rugby experts across the media.
“It is very special to win the award,” the Leicester Tigers back-row forward said. “It was unexpected but I will definitely take it.
“I feel like I have been playing some good rugby in a team that has been playing some good rugby and it is nice to get recognised.
“It has been going really well for the team, we have worked hard and when we have had an injury people have stepped up but we know there is a long way to go.”
Richard Cockerill, Tigers director of rugby, said: “We knew we were signing a very good player when we brought Thomas in during the summer and I’m delighted that he’s settled so well.
“He has been playing well, he gives us a good balance in the back row, he is enjoying his rugby and his family like it here.”
Waldrom began December with a vital try in Tigers’ 23-14 Aviva Premiership Rugby win away to London Irish and was instrumental in the victory over Sale Sharks at Welford Road later in the month.
Rugby World editor Paul Morgan, who chairs the voting panel, said: “Since arriving from New Zealand, Thomas has really lived up to his nickname of ‘The Tank’ marauding around the Aviva Premiership Rugby and contributing to his team’s recent impressive performances.
“He is world-class in the tight but what sets him apart is his love of the open spaces, where he is a sensational runner, and up there with the most consistent players in Europe. A very well deserved winner.”
Heather Smith, head of sponsorship for Premiership Rugby sponsors Aviv, said: “Thomas’ work ethic and attitude is symptomatic of Leicester Tigers’ approach to the game. He has been a consistent performer and who strives to give 100 per cent in every match.”
