The versatile big man joins the club after taking out Waverley Blues’ best and fairest last season in the Eastern Football League.

Leahy, 28, is set to hold down a key defensive post in a huge boost to the Saints’ prospects of pressing for finals actions for the first time since 2006.

Co-coach Leigh Corcoran said the 192-centimetre recruit’s experience would be invaluable as the club attempted to build on last year’s five wins.

“Another key defender was high on our wish-list and to be able to sign Hamish on the eve of the season is a significant boost,” Corcoran said.

“He is fairly mobile and will help create a lot of run and carry from across half-back.

“Structurally, it also enables us to free up Matty Dussin to perform other roles.

“Being an experienced defender it gives us a good mix down back and complements our younger talent.

“He is coming off a good season after winning a best and fairest and we are rapt to have him on board.”

Leahy has spent the past two seasons with Waverley Blues.

He will make the weekly trek from Melbourne and train with the Saints’ other Melbourne-based players.

Leahy joins Christian Burgess, Jarrod Hayse, Brody Ricardi, Billy Williams, Scott Lucas, Ben McIntyre and Tristian and Nick Purss in a productive off-season for the Saints.

Matt Spencer and Lee Dale are the biggest losses.

The Saints will host Grovedale on March 15 in their first practice match and travel to Wodonga Raiders for their season opener on April 5.