What impressed Stanton the most about his month was his consistent approach.
"I didn't give away too many at-bats," the slugger said. "When I did, it was boom, forget about it, and come back. I thought I was very disciplined. I was smarter in key situations and important situations for the team."
The award was announced on Sunday, and Stanton received the recognition for the first time in his career. The highest distinction he previously received was NL Player of the Week for the week of Aug. 9, 2010.
"When I got Player of the Week, I was like, I don't know if I can play any better than that," Stanton said. "I thought Player of the Month would be something way out there. It was a long process, and I played well and I helped us win a little bit. It was awesome. Just keep it going."
The 12 home runs matched Dan Uggla's number (2008) for the most homers ever by a Marlin in May. And his 30 RBIs equaled a club mark first set by Miguel Cabrera in 2006.
Stanton had a slugging percentage of .769 to go with a .432 on-base percentage.
During the month, he delivered a walk-off grand slam to beat the Mets on May 13. He also blasted a grand slam off Colorado's Jamie Moyer that knocked out light panels on the auxiliary scoreboard in left field at Marlins Park.
Producing big power numbers is something expected for Stanton. He's especially pleased that he was able to hit .343 over an entire month.
"That's something I'd never done before," he said. "You have to go back to like high school, or Little League. I played great. I just have to keep it going. It can't end here."
Stanton finished ahead of the Giants' Melky Cabrera, who hit .429 in May, and the Rockies' Carlos Gonzalez, who hit 10 homers and drove in 26 runs in the month.
Joe Frisaro is a reporter for MLB.com. He writes a blog, called The Fish Pond. Follow him on Twitter @JoeFrisaro. This story was not subject to the approval of Major League Baseball or its clubs.