Driving the Hancock Racing Ford Mustang Trans Am, he led all eight laps of a dramatic third Series Race of the weekend, having also prevailed in the Trophy Race on the afternoon prior.
John Adams (Ford Falcon XY) put a move on Tony Karanfilovski (Ford Mustang) for third place when the field arrived at Griffins Bend for the first time and Andrew Fisher (Holden Torana) followed.
Johnson was almost two seconds up after Lap 2 and while Hansford tried to respond, the gap blew back out to 2.5s at the end of Lap 7.
‘Junior' then cruised to a victory which made him the first driver to sweep a round since TCM went to its current four-race format, five years ago.
Hansford extended his series lead over John Bowe by finishing second at 0.7485s back, with Fisher third at nearly another six seconds in arrears, Miedecke fourth, and Bowe (Holden Torana) fifth.
It was a wild race for a number of other runners.
Danny Buzadzic (Holden Torana) spun into the wall at The Cutting after early contact with Cameron Tilley (Valiant Pacer), who would later pit having lost his windscreen.
Ben Dunn was in the mix early on before his Chevrolet Monza spat its left-rear wheel off as he ran along pit straight in sixth position on Lap 7, and Karanfilovski was last classified finisher in 11th after fizzing through the infield gravel trap at The Chase.
Round 6 takes place at the Valo Adelaide 500 on December 1-4.