The Cats' skipper, who previously won the award in 2010 and last season, polled 304 votes to edge out key forward Tom Hawkins (294) and midfielder Mitch Duncan (289.5).
"I've loved this footy club for a long time, and it hasn't sunk in," Selwood, who grew up as a Geelong supporter, said after receiving his medal.
"It's obviously a huge honour."
Selwood became the seventh player to win three or more best and fairest awards for the Cats.
Garry Hocking holds the club record, having won the 'Carji' four times, and Selwood now has that record in his sights.
"The little accolades along the way … I mean you pat yourself on the back quickly, but then you move on pretty quick, too," he said.
"We didn't win (the premiership) this year, and that burns."
Veteran defender Corey Enright (288.5), a two-time winner of the award, was fourth, while key backman Harry Taylor (287) was fifth.
Selwood was awarded best on ground honours by Geelong's coaching staff in nine of his 24 games.
The 26-year-old missed just one game in the recently completed season. He led the Cats when it came to disposals (614) and he kicked the third-most goals (24).
He finished equal-fourth in the Brownlow Medal and was last month named captain of the All Australian team.
Selwood will lead an Australian side against Ireland in an International Rules in Perth on November 22.
The Wash-Up: Geelong
Hawkins also had a brilliant season, bouncing back from the back problems that marred his 2013 campaign.
The big forward finished second in the Coleman Medal race with 68 goals. He was named the Cats' best player in four matches.
“(I am) really proud of the year that 'Hawk' played," Selwood said. "At times it was sort of a one-out forward line."
The hard-running midfielder was second behind Selwood at Geelong for disposals (547) and was twice named his team's best player by the coaching staff.
"His first three games weren't up to scratch," Selwood said. "He was questioning, 'Is this role made out for me? Am I putting too much pressure on myself?
"But he finally got his stuff together and, you know what, he found the way that he wanted to play.
"He was really important for us late in the year. He was one of our stronger players. He's obviously a huge runner and can run both ways.
"He's only 23. It's pretty scary what he will be."
TOP 10
1. Joel Selwood (304)
2. Tom Hawkins (294)
3. Mitch Duncan (289.5)
4. Corey Enright (288.5)
5. Harry Taylor (287)
6. Jared Rivers (285.5)
7. Jimmy Bartel (285)
8. Cameron Guthrie (278.5)
9. James Kelly (278)
10. Tom Lonergan (268.5)
OTHER AWARDS
Coach’s award: Joel Selwood
Tom Harley award (best clubman): Corey Enright
Best young player: Cameron Guthrie
Community champion: Mathew Stokes
VFL best and fairest: Jordan Schroder
Twitter: @AFL_AdamMcNicol
