The R.O. Shearman Medal is named after the former Sturt player Bob Shearman, who won five premierships and is a member of the SANFL Hall of Fame.
Since its incepetion in 2000, the Medal has been voted for by the League's senior coaches on a 5-4-3-2-1 basis for the best players in each game of the home-and-away season.
Summerton becomes the first Port Adelaide player since Ryan O'Connor in 2001 to win the medal, having polled in every game of the minor round.
He effectively joins Port Adelaide's AFL midfielder Robbie Gray, who recently won the AFL Coaches' Association's Champion Player of the Year Award, as being acknowledged as his competition's best player by arguably its best judges.
The Port Adelaide SANFL captain finished the year as the League's leading ball-winner and remains one of the favourites for Monday night's Magarey Medal count.
"Firstly, I'd like to thank the family of Bob Sherman, what a massive honour it is to win this award, it's something I definitely wasn't expecting," Summerton said.
"Obviously the other SANFL coaches for chucking a few votes my way, I really appreciate it, and it's means a lot to get that sort of respect from such respected people.
"The Port Adelaide Football Club - we've been through our ups and downs - but there's no other club I'd ever want to be at.
"I've really enjoyed my time there this year, hopefully I've got a few years left in me.
"And to my girlfriend Carly, Mum and Dad, my brothers, family and friends - thanks for all your support over the years as well."