 He served as an Assistant U.S. Attorney for the Central District of California from 1974 to 1978, and was Chief of the Special Prosecutions unit from 1977 to 1978, when he left to return to Hughes Hubbard as a partner.On October 27, 1997, President Bill Clinton nominated Matz to a seat on the Central District of California vacated by Harry Lindley Hupp.Matz was unanimously confirmed by the Senate on June 26, 1998 and received his commission on June 29, 1998.