On film, O'Neill co-starred in the Amblin Entertainment film "Little Giants", along with Rick Moranis; starred with Nick Nolte in "Blue Chips": and was featured in "Wayne's World" and "Wayne's World II". He has also appeared in "Cruising", "Dogs of War", "Disorganized Crime", "K-9," "Sibling Rivalry" and in the title role in "Dutch". O'Neill also starred in the Tiffany Theater's production of David Mamet's play "Lakeboat".