Assistant coach Dean Laidley is the latest departure from St Kilda, joining AFL rivals Carlton.
Laidley, the former North Melbourne premiership player and senior coach, will work under Mick Malthouse in charge of the Blues' midfield.
Earlier this week, Collingwood confirmed they had lured veteran sports scientist Bill Davoren from the Saints to be their new high performance manager.
The Saints then announced on Thursday former Melbourne Victory official Adam Basil as his replacement.
The Saints are in a period of significant transition on and off the field, with veteran midfielder Nick Dal Santo joining North Melbourne through free agency.
They were busy during the trade period and will go into next month's national draft with three first-round picks.
Football manager Greg Hutchison has also left, while chief executive Michael Nettlefold is about to leave.
Peter Summers has also replaced Greg Westaway this season as president.
Laidley was an assistant at St Kilda for two seasons.
The 1996 Kangaroos premiership player coached North from 2003-09, including a 2007 preliminary final appearance.
He then had an assistant's role at Port Adelaide before joining the Saints.
Laidley has a long association with Malthouse, having played under him at West Coast and also been one of his assistants at Collingwood.
"Dean has vast football experience as both a player and coach, and we believe he is the right man to take Carlton's midfield forward over the coming years," said Blues football director Andrew McKay.
"With Dean coming on board we have been able to reshuffle our coaching structure, with John Barker and Brad Green both taking on new roles."
Barker will now become Carlton's back line coach and Green will look after the forwards.Rob Wiley is their coaching and development director.