Marcie Cooper was the granddaughter of Dan Richards, the original Manhunter. As a teenager, she was recruited to join the Manhunters, the alien organization which had previously manipulated Richards and various others and which was secretly attempting to dominate the Earth. Appealing to Cooper's greed, the Manhunters got her a job working alongside Molly Mayne, the original Harelequin, at KGLX radio, a position she used to enable her to get to know Obsidian and Northwind of Infinity, Inc. and infiltrate the group's circle of friends. When the Manhunters launched their offensive against Earth, Cooper used Mayne's illusion casting glasses to become the new Harlequin and attack Infinity Inc, also attempting to murder her own grandfather along the way. She subsequently joined Injustice Unlimited and engineered the murder of Skyman by Solomon Grundy, but Injustice Unlimited were eventually defeated by Infinity Inc and Harlequin badly beaten by Grundy, who realized he had been used. Cooper was taken into custody and has not been seen since.
- Although this character was originally introduced during DC's Earth-Two era of publication, their existence following the events of the 1985–86 limited series Crisis on Infinite Earths remains intact. However, some elements of the character's Pre-Crisis history may have been altered or removed for Post-Crisis New Earth continuity, and no longer apply.
- 15 Appearances of Marcie Cooper (New Earth)
- 2 Images featuring Marcie Cooper (New Earth)
- Quotations by or about Marcie Cooper (New Earth)
- Character Gallery: Marcie Cooper (New Earth)