The 19-year-old striker made his debut in the 4-0 win over Shrewsbury in the first round of the Capital One Cup in August and scored his first professional goal against Nottingham Forest last September at Elland Road.
Poleon also spent time on loan with League One Bury scoring 2 goals in 8 appearances.
Poleon said on the Leeds United official website: "I'm glad to be tied down and commit my future here, hopefully I can push on now."