He first made state selection in the 1983 New South Wales senior men's eight contesting the King's Cup at the Interstate Regatta within the Australian Rowing Championships.

[1] He made every New South Wales King's Cup crew from 1983 to 1987[2] and rowed to Australian championship victory in that boat of 1984.

With Steve Evans, Jim Battersby and Rick Goodrich, in an all-Mosman crew Muller won the Australian national coxed four title in 1984.

[7] The Australian eight selected for the 1984 Los Angeles Olympics was built around the national champion Mosman Rowing Club coxed four of Muller, Jim Battersby, and Steve Evans.

[10] For the 2023 season he rook a role as Rowing Caretaker and Boatshed Manager at St Joseph's College, Hunters Hill.