After graduating from university in 1980, he moved to London where he appeared in a number of productions, including in Eugène Ionesco's Rhinoceros' at the Croydon Warehouse Theatre.
He was a member of the Company of Ten theatrical group and appeared with them in Translations by Brian Friel, A Streetcar Named Desire, and God Only Knows by Hugh Whitemore.
He wrote the screenplay for the film Paradise Place (2013), a comedy about a soldier returning from duty in Afghanistan who finds that the street where he lived no longer exists.
Pagan's novel The Agency, formerly called Eat More Bloody Meat Y'Bastards!, is a satire based on his experience of office life in the advertising industry.
Using the pen name Michael McDonnell, Pagan wrote the Dermot O'Hara Mysteries, detective stories set in Kenmare, County Kerry.