He then became owner of a small hotel at the corner of Queen and Parliament St. From this he moved into the property business, where he made his fortune.

These included new parks and playgrounds, city owned farms to provide work for the unemployed, and an old aged home.

O'Neill was one of only a few Catholics in a Toronto politics that was then dominated by members of the Orange Order, but he gained enough interdenominational support to top the Board of Control vote on several occasions.

In the 1919 election O'Neill chose to run for mayor against incumbent, fellow Cabbagetowner, Tommy Church.

He chose instead to run provincially for the Ontario Liberal Party in the riding of Toronto Southeast - Seat A.