Johnson's 6-yard scoring grab was one of two fourth-quarter scoring strikes from Matthew Stafford that erased a 24-17 deficit and handed the Lions (9-5) their second straight win.
The victory enabled them to keep pace in the NFC playoff race.
Johnson finished with a career-high 214 yards on nine grabs.
Stafford (29-of-52, 391 yards, four touchdowns) began the comeback with a 3-yard TD pass to Titus Young with 5 minutes to play.
Detroit later went 98 yards on the decisive final drive, highlighted by Johnson's 48-yard reception.
Sebastian Janikowski tried a 65-yard field goal as time expired for Oakland (7-7), but it was blocked.
With the loss, the Raiders stayed one game behind Denver in the AFC West.