Former Adelaide star Graham Johncock has joined the centurion club after booting his 100th goal for the season in a South Australian reserves competition last weekend.

Playing for Mallee Park in the Port Lincoln Football League reserves, Johncock kicked 13 goals in his team's 116-point win over Lincoln South on Saturday in front of a huge crowd at Mallee Park Oval.

Johncock – who also serves as the club's president – slotted his 13th major of the day after taking a chest mark and kicking truly from a 45-degree angle.

When the ball sailed through, the 41-year-old was swarmed by dozens of spectators in jubilant scenes.

Mallee Park Football Club took to social media to state that they were proud of Johncock's achievement.

"Congratulations to our club president Graham on kicking 100 goals," the Facebook post read.

"We have all loved every minute (of) watching you play."

With Mallee Park winning two matches this season by forfeit, Johncock kicked 100 goals from 13 games at an average of 7.5 goals per game.

His season included a bag of 15 goals against Boston, two 13-goal hauls, plus 10-goal and 11-goal performances in consecutive weeks earlier in the year.

Johncock still wears the #18 guernsey, which he donned for 227 games at Adelaide across a dozen seasons at the elite level.

At his best, he was one of the better small defenders in the game however proved his versatility by winning the club's leading goalkicker award in 2003.

Johncock revealed in an interview with the Adelaide Crows a couple of years ago that he had always intended to return to his home club.

"Once I finished footy, I was always going to move back home to Port Lincoln," Johncock said.

"I got involved with my local football club, got involved in the community.

"I coached Mallee Park for a few seasons and was lucky enough to win a couple of premierships as well.

"It's awesome, running around with my brothers and cousins who I grew up playing with.

"I'm just enjoying winding down."

Mallee Park reserves finished on top of the ladder with just the one loss for the season.

The Eagles face Marble Range next weekend in a second semi-final clash with the winning team advancing to the grand final in three weeks.

The club's senior team finished in third spot and face Boston in an elimination semi-final on Saturday.