He studied architecture at the Ecole Politechnique Federale in Lausanne, where he met Alvaro Siza and Mario Botta, who offered Rosselli a job in 1979.
He left the next year to work for Mitchell/Giurgola in their New York office. He joined Furio Valich"s firm, then opened his practice a year later. His work has primarily been residential, but in the 1990s he worked on a series of restaurants.
He says that his approach to architecture is "humanist, where people and environment take precedence over preconceived design dogmas".