Part of the 1980s East Village fashion and art scene, Monaghan was friendly with artists including Andy Warhol.
He was Art Director for Fiorucci[3] where he collaborated with Antonio Lopez, Francesco Scavullo and Andy Warhol[4] on live windows and events in-store.
In 2011, Fales Library at New York University mounted an exhibition of Monaghan's paintings titled "At Moments Like These He Feels Farthest Away," a visual response to Tim Dlugos's poem "Gilligan's Island.
[15] In 2015, Landmark Arts at Texas Tech University Lubbock mounted an exhibition of Monaghan's paintings titled “Why Are You Doing This To Me?” which is a visual response to David Trinidad's poem "The Late Show".
In June 2013, Monaghan's Andrew Geller-designed beach house in Fire Island Pines was published by Elle Decoration UK[16] and in 2014 in Mid Century Modern Complete by Dominic Bradbury.