The 27-year-old Middlesbrough Academy product was Town's top scorer last season, netting twelve times in all competitions.
Having been released by his boyhood club, Fewster represented Spennymoor Town and Blyth Spartans in non-league, while also enjoying loan spells with Preston North End, York City and Hartlepool United during his time on Boro's books.
A representative of England at under-16, under-17, under-18 and under-19 level, the centre forward will be looking to kick on again in a blue Whitby shirt next season.
Manager Nathan Haslam has high hopes for Fewster in the 2023/24 campaign and hopes that he can add to his Seasiders tally.
He said: "For me, Fewster is the best striker in the league on his day. The key moving into next season is to get some consistency and if we get that Brad will be one of the best marksmen in the league.
"I think since that bad injury he picked up in 2019, it's been frustrating for everyone at the club as you want players like Brad on the pitch because if he's firing, we have got one of the best strikers in the league."