Johnstone joins from GroupM, the media agency and now producer, where he was director of entertainment for EMEA. He will be based in London in his new role.
“This is a really competitive market, but we think we still have a lot to offer,” Johnstone said. “Our goal is to work with broadcasters and producers to help bring brilliant ideas and stories to life.
“Mediapro is an exceptional company with enviable production experience and talent. Production budgets, particularly in scripted, are rising rapidly everywhere and we need to make quality shows more accessible”
Prior to GroupM, Johnstone was at Channel 4 and before that Turner, working at its kids channels.
A recapitaised Mediapro is expanding internationally. It appointed Laura Fernández Espeso its international chief in September and that followed the recruitment of former Keshet exec Ran Tellem, the opening of a new office in Argentina and a deal with Daniel Burman.
The company run the La Sexta free-to-air channel in Spain, and has production and distribution units Globomedia and Imagina.