Harcourt was appointed director of the Suicide Squad after Amanda Waller was placed under investigation following Max Lord‘s actions in Justice League vs Suicide Squad.
She was a double agent working for Direktor Karla, stealing Amanda Waller’s files on metahuman vulnerabilities, and she was able to persuade Captain Boomerang to become a double agent as well. It was on her orders that Boomerang murdered Hack, after Hack found out that Harcourt was a traitor.
Harcourt is later found out by Waller, but is killed by Boomerang before she could reveal who killed Hack.