Studied Art and Arts and Crafts before entering architecture at the Dublin Institute of Technology, graduating 1969. Established Gilroy McMahon in 1971. Received first price in the Department of Education architectural competition for generic solutions to the national community school brief (1975). Received the RIAJ Triennial Gold Medal in 1993 for the Extension to the Dublin Institute of Technology, Bolton Street, Dublin. He has lecturered in Ireland, the United Kingdom and Finland, and has taught at the Dublin Institute of Technology.