Bleakley quit Emap in October for a joint managing directorship at Viacom Outdoor, following head of radio Tim Schoonmaker, who left for a short-lived stint at Odeon Cinemas in January.
Stacey has risen through the ranks at Emap, holding a variety of roles including a recent post of radio sales controller.
However, Emap bosses will be playing catch-up again as the brain drain at the top of Emap has continued following Emap Advertising managing director Dave King’s defection to Telegraph Newspapers earlier this week.
In the short term, chief executive of Emap Consumer Media and chairman of Emap Advertising, Paul Keenan, will oversee Kings’ beat.
Dee Ford, managing director of Emap Radio said: "I am really looking forward to working closely with Karen and the broadcast team at this exciting time.
“Karen is the ideal person to help us move our radio strategy to the next level and ensure we are delivering creative and highly effective radio solutions for our customers.
“This is a key role which Karen well deserves.”
By Kevin May