Tesch has joined Razorfish as its executive strategy director to oversee a team of 16. His hire follows the departure of the head of strategy and planning, Adrian Gans, to Brand Union in January.
He most recently ran an innovation consultancy, called Tesch, along with his brother, Johan. The pair started one of the first digital creative agencies in 1996, the Stockholm-based Tesch & Tesch, but sold it to Lowe in 2002.
Tesch then joined Lowe Worldwide as its global digital strategy director, before becoming the digital strategy director at Fallon.
He said: "In a world where digital is everywhere, inspired strategic thinking will be instrumental in uncovering opportunities for a new dimension of creativity."