He was the assistant engineer on albums by The Badloves, Things of Stone and Wood, Deborah Conway, Tim Finn, The Black Sorrows and Chocolate Starfish, as well as the Australian cast recording of Jesus Christ Superstar.
He worked on albums by Tegan and Sara (This Business of Art), Feist (Open Season), By Divine Right (Good Morning Beautiful), Sarah Slean (Night Bugs), Starling (Stuff You Should Have Said Before) Elliott Brood (Ambassador), The Flashing Lights (Sweet Release) and Rascalz (Reloaded).
O'Shea also received critical praise for producing the mini-album by Toronto alt-rockers Hotel (My Demon Brother).
[8] Impressed by demos recorded in the band's bedroom, O'Shea returned to Melbourne in 2004 to work with Brilliant Fanzine.
In 2011, O'Shea produced a single for Paul Ruske featuring the Grammy Award-winning Soweto Gospel Choir at Iwaki Auditorium, ABC Studios, Melbourne.