The star Lion had already claimed the AFL Coaches' Association player-of-the-year award and became the first Brisbane player to clinch the best and fairest.
Adelaide's Anne Hatchard and Bates were tied on 18 leading into the final round, but while the Crow added two more votes, the star Lion claimed three.
Shaking as she accepted the award, Bates said she was in "shock" at claiming the honour.
"I know my name was being thrown around a little bit but that was a shock to me, and this is obviously the greatest honour you could ever achieve," Bates said.
"I was looking for improvement, and last year, as much as it was amazing winning a premiership, I was hungry to become a better player.
"Instead of just being a consistent player, I wanted to see what my true potential was.
"I made a lot of changes in the off-season, and I'm just happy that I could reap the rewards today."
Bates then looked out to her coach, Craig Starcevich, in the crowd, and reminded him that he had agreed to do a "shoey" if she won.
With a wry smile and laugh, Starcevich began removing his shoe and pouring champagne into it before downing the drink from it.
"I don't know how I'm meant to keep going after that but thanks Craig," Bates joked afterward.
AAP with The Project