Willock played for five League clubs before joining Vale last August

The 26-year-old had rejected the chance to extend his short-term contract at Vale Park in favour of a move to Peter Taylor's Blue Square Premier side.

Willock scored four goals in 20 appearances for Vale, who are currently bottom of League One.

"Callum was Peter's first choice for a strong, quick forward who knew how to play with his back to goal," chairman Phil Wallace told Boro's website.

"He obviously wants to get back into the League and is determined to do that with Stevenage."

The former Fulham, QPR, Brentford and Peterborough forward joined Vale in August 2007.