The 18-year-old joined in 2023 in a scholarship deal, moving from Chelsea’s academy.
Now the under-21s star has been rewarded for his impressive form so far.
After signing his deal, Sesay said: "I'm happy that I've been able to take this next step and hopefully there's more to come. I'd just like to thank everyone who has helped me out through this journey and I'm grateful for the opportunity."
Academy director Andy Goldie added: "Since joining us in the summer of 2023, Moses has continued to go from strength to strength with the under-18s and breaking into the under-21s squad, earning some exposure to first-team training in the first half of the season.
"He initially joined us as a winger, but has transitioned to performing consistently well at left back and across all three midfield positions, which is a testament to his character and the qualities he has developed."