Sergeant O'Shaugnessy was a police officer working for the Seaboard City Police Department who along with other citizens that survived the missile attack that devastated their city in 1962 became trapped in a virtual-reality recreation of Seaboard City that Ray Thompson, a mutated child who idolized the Justice Guild of his world, created with his mental abilities. His constant job was to contact the simulated Justice Guild of any possible threats to the city, whether it be from the Injustice Guild
(also a simulation) or otherwise. When the Justice League members from their own world appeared in that of the Justice Guild and exposed Seaboard City as being a fantasy recreation, the recreated Justice Guild turned on Ray Thompson and overpowered him with such force that it incapacitated Ray, causing the Justice Guild to vanish and the recreated Seaboard City to be restored to its original devastated appearance, thus freeing its actual citizens from his control, including O'Shaugnessy.
- In the Seaboard City recreation, O'Shaugnessy spoke with an Irish accent. When Seaboard City was restored to being ruins, he spoke without an accent.
- Appearances of Sergeant O'Shaughnessey (DCAU)
- Images featuring Sergeant O'Shaughnessey (DCAU)
- Quotations by or about Sergeant O'Shaughnessey (DCAU)
- Character Gallery: Sergeant O'Shaughnessey (DCAU)