He is moving to take a position as the creative head at an as-yet-undisclosed agency.
Bildsten was the creative director in Minneapolis for seven years and became the executive creative director last year. At Fallon, he created award-winning work for BMW, Porsche and Timex. Work for the Public Broadcasting Service won him two Outstanding Commercial Emmys.
Pat Fallon, the chairman of Fallon Worldwide, said: "For some time now, Bruce has shared his desire to be the number-one creative in an agency. He is now leaving to make that happen."