De Wolf, who will report to the executive creative director, Matt Keon, will work across 18 Feet & Rising's client portfolio including LoveFilm, Nationwide and Virgin Media.
He started his career at Marketforce in Perth before joining Clemenger BBDO in Melbourne and then McCann Erickson Sydney.
After that, he became the creative group head at Saatchi & Saatchi New Zealand.
De Wolf took up the creative group head position at JWT Sydney in March last year and worked on accounts including Kellogg Australia.
Keon said: "We've been looking for someone who can help take us to the next level for a while. There are only three people in the world who I want to help us achieve that. Stephen is one of them. I have been trying to get him to London for over a year and he has finally come to his senses."