LONDON—Mischief has concluded its search for Mitchell Kaye's successor by hiring Frankie Cory as the PR firm's new CEO.

Cory joins Mischief from Citizen Relations, where she was UK CEO. She arrives at the Engine Group agency following the departure of founder and CEO Mitchell Kaye earlier this year.

"Mischief is creative, bold, entrepreneurial and ambitious," said Cory. "All the characteristics of small-agency culture that I really love and admire; with the scale and track record of a large agency."

Cory joined Citizen Relations in 2011 after a six-year stint at Frank. She became CEO of the agency, which is owned by EDC, in 2012. Prior to Frank, where she became MD, Cory was creative director at Cohn & Wolfe.

"Frankie joins at an exciting time for the agency as it looks to use the Engine model to increase Mischief’s offering and give its ideas the impact they deserve," said Engine CEO Debbie Klein.

In an interview with the Holmes Report following his resignation, Kaye said that he was involved in the search for his successor. He also said that Mischief's continued success — the firm grew 20 percent in 2012 — would require it to "better utilise the assets around them" at Engine.

After launching in 2006, Mischief is now worth upwards of £6.5m, employing 70 people and working for such clients as Unilever, Birds Eye, AkzoNobel and The FA.