A native Montanan, William holds a D.M.A. in Opera Production, University of Washington. He has sung supporting and leading baritone roles with New York City Opera National Company, Seattle Opera, Banff Centre for the Arts, Boston Lyric Opera, Opera Columbus, Des Moines Metro Opera, Utah Festival Opera, Tacoma Opera, Houston Opera in the Heights, Opera Idaho, Anchorage Opera, and Rimrock Opera Company. Most recently, William sang the roles of Sam in Trouble in Tahiti and Ben in The Telephone in RO's 2010 Summer Opera Festival. Other baritone roles include Escamillo in Carmen and Giorgio Germont in La traviata. He sang in Abilene Opera’s Carmen, as Zuniga; La fanciulla del West as Jake Wallace; and Peter Pan as George Darling. William’s opera production and stage direction credits include Street Scene, under the baton of Opera Cleveland's Dean Williamson, The Mikado and H.M.S. Pinafore, The Face on the Barroom Floor, Così fan tutte and La finta Giardiniera, The Fiddler on the Roof, Oklahoma, Peter Brook’s The Tragedy of Carmen (La tragédie de Carmen) and Die Fledermaus. Mr. Mouat recently sang Count Monterone in RO's Rigoletto. William is Education Director for Alberta Bair Theater.