Benton, who arrived as hapless maths teacher Daniel Chalk in May last year, will make his final appearance two thirds of the way into the current eighth series.
Waterloo Road's official Twitter account made the announcement earlier this morning (September 20), while a BBC spokesperson also confirmed the news to Digital Spy.
Chelsea Heeley, who plays Chalky's love interest Janeece Bryant, is making her on-screen departure next week after her exit was announced in May.
During a recent interview with DS, Benton promised a "very positive outcome" for his character, and insisted that "Chalky's best episode" is yet to come.
After realising that he wants to become a father, Chalky develops a close bond with schoolboy Kevin, whom he later considers adopting.
Waterloo Road airs on Thursday nights on BBC One.