With a BA (drama, history) from the University of Sydney, Summons became a high school teacher of English, ESL, history and drama, and lectured in drama writing at the Sydney Institute of Technology (now UTS). He wrote adult and children's plays for many years, which were produced by a number of Sydney's leading theatres, including the Ensemble Theatre where he was also playwright-in-residence at one stage. Summons's first professionally produced play was The Coroners Report in1977, followed by Lamb of God in 1978, and 'The Sower and the Reaper' in 1980 for the Festival of Sydney Playwrights. He co-wrote a comedy farce, 'The Critic', with Jennifer Pilon. His plays were produced for radio by the ABC. Summons has also written e-books for children.
Summons's keen interest in theatre-in-education is clearly demonstrated by his play Massacre at Myall Creek, which toured various states of Australia for several years and played to many thousands of students. A member of the Australian Writers Guild, and with an interest in computers, e-learning and software development, Summons programmed and authored the CD Teacher's P.E.T. for the Australian Commonwealth and NSW governments to help students with literacy problems, using new technologies to deliver directly to a wider audience. In 2006 he received an award from the NSW Department of Education for excellence in the integration of information and communication technologies in the classroom.