Chase has been portrayed by Josh Swickard since the character's debut on February 21, 2018.
Amanda Setton, known for playing Kimberly Andrews on One Life to Live, came into the contract role of Brook Lynn Quartermaine on November 18, 2019. When Setton temporarily exited GH on August 4, 2020 for maternity leave, Briana Lane was cast to play Brook Lynn from August 6, 2020 - November 16, 2020. Setton returned as Brook Lynn on March 15, 2021.
On January 14, 2020, as Detective Harrison Chase showed up to break up a fight, Brook Lynn accidentally hit him in the head with a beer bottle while aiming for Linc. Chase arrested Brook Lynn, Lulu, Dustin, and Linc for their bar fight.
At the PCPD, Brook Lynn told Chase that she didn't mean to hit him with the beer bottle and that she was aiming for Linc but Chase thought she was merely spinning a tale. Ned showed up and after learned what happened he initially told Chase to lock her up.
On March 20, Lulu sprayed Brook Lynn with champagne and they got into a huge fight. Valentin Cassadine was recording their fight and the PCPD went to break it up. Sadly, when Brook Lynn accidentally hit Detective Chase in the face, she was arrested and put in jail.
The next day, Brook Lynn was released by Chase who decided to give her a break because she had been publicly humiliated on the paper and internet.
On September 25, Brook Lynn, now up and about, runs into Chase and Sasha at GH on her way to an appointment, and calls Chase her roomie. Both she and Sasha claim nothing is going on between them and Chase, but neither believes the other. Chase then tells Brook Lynn that Nelle is dead. Brook Lynn says that while she is sorry for the loss of any human life, she is also relieved, echoing Chase and Sasha's feelings. He leaves them to go the morgue.
On October 14, Amy secretly shows up at a "Deception" buyer pitch, wanting to see everyone react to her song. Brook Lynn convinces her to stay out of the way, and hiding behind a door in the Metro Court, Amy watches the chaos of the sales pitch, including Lucy claiming Brook Lynn can sing for the buyer right then and there. She secretly got Amy to agree to sing and use bluetooth to connect her voice to Brook Lynn's mic. Unfortunately, they're caught when Chase shows up. The buyer walks away, and Lucy angrily fires Brook Lynn from "Deception."
On November 13, Brook Lynn saw Chase at the hospital and revealed that she's leaving town. Chase wanted her to make things right with her family because she won't feel good until she does. When Brook Lynn learned that Chase never slept with Sasha, she urged him to tell Willow the truth and let her make up her own mind on who she wants to be with. Chase asked Brook Lynn to join him and she agreed to.