Interesting name, doesn’t appear in any name databases I can find except as a variant of Conan and this guy wasn’t Irish.
I hadn’t heard of him, either, or that name (which is Conone in Italian and Conón in Spanish), for that matter.
According to Wikipedia, Pope Conon met with and consecrated as a bishop an Irish missionary who went on to be canonized as Saint Kilian, so maybe the name Conan became popular in Ireland because of Pope Conon.