Associate Robins, Davis & Lyons, Minneapolis, 1962-1967. Principal Gurstel & Gurstel, 1967-1997. President Marc Shawn, Inc., 1997—2003, Q, LLC, 2003—2006, Q, Boutique, since 2007.
Arbitrator Hennepin County District Court, 1988-1991. Parttime referee family court Hennepin County District. Lecturer University Minnesota Family Law Seminar.
Member American Bar Association (corporation banking and business law and family law sections), Minnesota Bar Association (co-chairman family court committee bankruptcy law section 1966-1967, family law and bankruptcy law), Hennepin County Bar Association (chairman family law committee 1964-1965, vice chairman 1981-1991, fee arbitration board, creditors remedy committee), Federal Bar Association, Association Trial Lawyers American, Minnesota Trial Lawyers Association, American Academy Matrimonial Lawyers, National Council Juvenile and Family Court Judges, Commercial Law League American (recording secretary 1980-1981, board governors 1983-1989, president 1987-1988), Commercial Law League Fund for Public Education (secretary 1981-1983, president 1989-1992, board directors 1989-1994), Phi Delta Phi. Clubs: Oak Ridge Country (Minneapolis). Lodges: Shriners, Masons.