Michael Ryan was sickly as a youth, as he had difficulty recovering from a burst appendix. He attended Belvedere College in Dublin, noted for its sports, but never played any of them because of his health issues. But one day he and his brother began fighting in their garden with sticks, in a form of fencing, and Michael decided to take fencing lessons, beginning épée training in 1962. He eventually won the Irish Championship seven times with the épée, winning in 1962-65, 1967-68, and 1975. He also won the 1964 Irish Open with the épée, and competed at the 1963 Junior World Championships, placing ninth. Ryan fenced for Ireland at both the 1964 and 1968 Olympics, competing with all three swords. During that time he was studying mathematics and theoretical physics at University College Dublin and later became a lecturer in mathematics at Waterford RTC from 1971-80. He had previously worked as a statistician at the Irish Central Statistics Office, and after 1980, became head of the computer section at Dublin City University for 16 years.