The changes follow the promotion of Ben Kay, who was named an incoming joint chief executive alongside Alison Hoad in September last year.
Huntley has been at RKCR/Y&R since 2002. She worked on the current "when it's worth watching, watch it with us" campaign for BBC One.
Murray joins RKCR/Y&R from Wieden & Kennedy, where he was the global planning director on Nokia. Before that, he was at Adam & Eve and also spent four years at Bartle Bogle Hegarty.
He will work closely with Emily James, also a joint head of planning, when she returns from maternity leave.
The agency has also hired Don Larotonda as a board planner to work on Marks & Spencer, Volvic and the BBC. He was previously the strategy director at Mindshare, where he worked on the First Direct campaign that won a gold Lion at Cannes in 2011.
Kay said: "Alice, David and Don embody the future of planning at the agency: superb strategic and creative talents with top-class credentials."