O'Toole has been a vital cog in Golden Square's five-year domination of the Bendigo Football League, but at age 35 believes the time is right to rejoin his home club, Ultima, which is coached by his brother, Luke.

"I've got family up at Ultima, so it was always going to be a bit of a lure to go back there," the modest O'Toole said on Thursday.

"I've been very fortunate to have been at Golden Square during what has been a successful era, so it was hard to tell them I was leaving, but they understood."

O'Toole joined Golden Square in 2005 and kicked 357 goals for the Bulldogs, including 87 in 2006 when he won the BFL's Ron Best Medal.

As well as playing in all five Golden Square flags between 2009 and this year, he won the VCFL Medal in the Bulldogs' 2011 grand final win over Eaglehawk.

He has played 338 senior games, taking in stints at Ultima, where he won flags in 1996, 2002, '03 and '04, Tyntynder (flag in 1999), the Bendigo Diggers in the VFL and Golden Square.

O'Toole is the second five-time Golden Square premiership player to leave the club in the past month after Mark Lloyd's move to Wedderburn in the North Central Football League.

And like Lloyd, O'Toole leaves with Golden Square's best wishes.

"We were well aware for some time that he wanted to play some footy back at home with his brother and that opportunity has come up," Golden Square coach Nick Carter said.

"Matty O'Toole has been a legend at Golden Square and will go down as one of the best big-game players I've seen.

"We bandy the words legend and champion around, but he definitely ticks those boxes. It seemed the bigger the game, the better Tooley played."