The 17-year-old, who has made two substitute appearances for the Chairboys this season, saw off competition from Aldershot's Henrik Breimyr and Oxford's Aaron Woodley to take the title.
Harris said: "I'm chuffed to bits.
"I was playing Sunday League football in West London last year so I've gone from the bottom of the ladder and it's a dream come true."
Meanwhile, Wycombe captain Gareth Ainsworth was pipped to League Two player of the year by Bury striker Ryan Lowe.
Source: PA
Source: PA