The award was presented by Mark Teixeira, Granderson's teammate and a member of the MLBPA's executive board.
The award is named after the former executive director of the players' union and honors performance on and off the field. Granderson was selected by a secret ballot of all Major League players.
"It's amazing that not only my recent teammates in Detroit knew what was going on, but other players around the league also knew," Granderson said. "That's a big thing, because they're not around me all the time. Somehow, someway they caught wind of some of the things I was doing and thought me worthwhile to vote for."
Aside from slugging a career-high 30 home runs in 2009, Granderson released a children's book and continued working with his Grand Kids Foundation, which promotes baseball and education in inner cities.
Granderson beat out fellow finalists Torii Hunter and Albert Pujols for the award.