The Holden driver secured the crown after a third-place finish at the season finale Sydney 500 at Sydney Olympic Park, which was won by Shane van Gisbergen.
The experienced Jason Bright produced a superb drive to finish second.
But the day belonged to Whincup, who joins the late Ian Geoghegan, Dick Johnson and Mark Skaife as the only five-time title winners in Australian touring car history.
Only needing to finish in the top 21 to secure the crown Whincup, who tore up the street circuit all weekend, did it easy to finish on the podium after starting from third on the grid.
"Unbelievable," Whincup told Channel Seven.
"It's just a huge team effort.
"It's been a tough year without doubt for everyone.
"A big thanks to Lowndesy - this is just as much his as it is mine. Wow, number five, I can't believe it."
Red Bull team-mate Craig Lowndes, the only driver capable of catching Whincup for the title pre-race, could only manage a fifth place finish to end the season as runner-up.
Ford's Will Davsison came home seventh in the final race to finish third in the standings, with team-mate Mark Winterbottom came home sixth to finish fourth overall.
Jamie Whincup driver of the #1 Red Bull Racing Australia Holden does a burn-out after winning the championship in the Sydney 500. Photo by Matt Blyth/Getty Images
Jamie Whincup driver of the #1 Red Bull Racing Australia Holden celebrates winning the championship after finishing third in the Sydney 500. Photo by Matt Blyth/Getty Images