Brooks is a Scotland international who has played for Rochdale and Whitehaven.
Widnes coach Debis Betts’ said Brooks’ signing strengthens his squad.
“Sam has a great desire to be a full-time rugby player, this shone through in training sessions that he took part in,” Betts said.
“We were willing to offer an opportunity and further our relationship with Whitehaven. From the information we acquired on Sam we believe there is potential for Sam to become a Super League front rower.
“We’d like to thank Whitehaven for developing Sam’s talent over the last season.”