The Browns have signed the quarterback to the 53-man roster, the team announced on Wednesday.
Walker has helped the Browns win consecutive games while on the practice squad. He had run out of standard elevations from the practice squad after Sunday's victory over the Colts.
After being released by the Bears at the start of the regular season, Walker joined Cleveland's practice squad. He was elevated to the gameday roster for the Week 4 loss to Baltimore before starting the Week 6 win over the 49ers.
Walker has completed 33-of-66 passes for 370 yards with three interceptions for Cleveland this year.
Cleveland has also signed running backs Nate McCrary and Jordan Wilkins to the practice squad.