Patterson studied law at Bristol and played for English Universities and British Universities. He rejoined Instonians on his return to Ireland and was selected for Ulster and capped by Ireland B in 1977 before winning his first full cap for Ireland against New Zealand in 1978. He won eleven senior caps and scored five tries for Ireland. His career came to a premature end when he suffered a serious knee injury playing against Griqualand West during the 1980 British Lions tour to South Africa, after having been scrum-half in the first three internationals against South Africa.