The foundations of his success were laid in the sixties, when he trained in London and Oslo and began to exhibit widely. He was a founder member of the New Artists’ group in 1962 and Dublin’s innovative Project art Centre in Dublin in 1967. He was a core member of Graphic Studio Dublin during its growth years from the mid 1960s. Behan has been awarded many honours and became a Member of the Royal Hibernian Academy in 1990, having been an Associate of the Academy since 1973. He is also a member of Aosdána.

In June 2000 he was awarded an honorary doctorate from the National University of Ireland, Galway on the same day his large commissioned sculpture, Twin Spires, was unveiled at the college.

his major public commissions include Flight of Birds, Famine Ship, Tree of Liberty, Daedalus, Millennium Child, Arrival and Equality Emerging, (unveiled in Galway city in November 2001).