The 23-year-old Sunderland Academy product initially joined the Seasiders in 2019, on loan from the Black Cats, before returning on a permanent deal in August 2021 following his release from the Academy of Light.
Hackett made 21 appearances for Town last season, before linking up with Hebburn Town on loan from December 2022 until the end of the season, winning the Durham Senior Cup while with them.
Hackett departs with the best wishes of everybody at Whitby Town and the club thanks him for his service.