The 21-year-old wrote on Twitter that he had filmed his final scenes as Gaz Bennett for the Channel 4 soap.
"So that's it," he wrote. "Cast/crew old and new gunna miss u all, had 3 top years and learned a lot! Much love! (sic)"
He later posted to his followers: "Thanks for all your messages x hopefully be in something else soon, fingers crossed."
Goonan made his first appearance as the Hollyoaks villain back in November 2008.
He briefly left the soap in 2010 when Gaz was wrongly imprisoned for the murder of Calvin Valentine (Ricky Whittle), before making his on-screen return in January.
Recent plots have seen Gaz strike up a romance with Heidi Costello (Kim Tiddy) and put her son Seth (Miles Higson) in hospital after selling him illegal steroids. Get the Inside Soap magazine on your iPhone or iPad