Brentford have extended Chris Long's loan spell from Everton until the end of the season.
Murray, who made more than 400 appearances over two separate spells with the Championship outfit, became a fans' favourite during his time as a player with the Robins.
And Derek McInnes expects him to inject his own brand of energy into the City dressing room.
The Robins boss told the club's official website: "Scott was the first person I thought of when we were looking for a new kitman. I believe the role is a valuable member of the team; they're at the heart of everything, in the dressing room and on away trips.
"My last kitman (at St Johnstone) was someone I could really trust and did the job brilliantly, and that's why I'm delighted Scott decided to accept my offer.
"He's certainly got the personality and charisma for the role, he's bubbly and outgoing, but he's also got the club at heart which is invaluable. I'm sure the supporters will join me in welcoming him to the role and I'm looking forward to working with him."