Robert Johnson studied the French Horn at the NSW Conservatorium of Music with Alan Mann, for whom the Alfred Hill Horn Concerto was written. After holding the positions of Principal Horn with the West Australian Symphony Orchestra and the Australian Opera and Ballet Orchestra, he was appointed as Principal Horn with the Sydney Symphony Orchestra in 1986, a position he still holds. During his time with the SSO, he has performed as soloist in works by Mozart, Strauss, Britten and Ross Edwards on both Regional Tours and at the Sydney Opera House. He has also appeared as Guest Principal with all the major Australian Orchestras, The Australian Chamber Orchestra and the New Zealand Symphony. As a teacher he has worked as Horn Lecturer at the NSW Conservatorium of Music and Canberra School of Music and has appeared as Artist in Residence at Universities and Music Schools in Brisbane, Hobart, Melbourne, Perth and Hong Kong.