Mr. O'Toole is a wealthy individual descended from one of the founding members of the Sons of Erin Society.
Mr. O'Toole received Burnt Toast in the mail. While he was clueless, O'Toole's housekeeper recognized the ill omen. Later that day, the Leprechaun arrived at his penthouse and conjured a Shillelagh Emanation. O'Toole took the edge of his balcony and was mistaken as suicidal. The Extreme Ghostbusters arrived and saved him from the emanation. However, the Leprechaun trapped him in his pot. Once the Leprechaun was trapped on St. Patrick's Day, Mr. O'Toole was released.
- In the first draft of "The Luck of the Irish]]", Mr. O'Toole was described as a successful builder.
- On page five of Ghostbusters Volume 2 Issue #14, the Mr. O'Toole makes a non-canon cameo as the pedestrian crossing the street towards Pequod's.
- Housekeeper (1997). Extreme Ghostbusters- The Luck of the Irish (1997) (DVD ts. 02:45-02:49). Sony Pictures Home Entertainment. Housekeeper says: "Heaven help you, Mr. O'Toole!"
- Wachtel, Brooks (1997). Extreme Ghostbusters "The Luck of the Irish" (First Draft 1997) (Script p. 05). Line reads: "THE MAIL - on a silver salver - is carried by an OLD IRISH MAID to Mr. O'TOOLE, a successful builder."