Toronto's Luminato arts festival is being hailed as a great success, but behind the scenes one of Luminato's founders was struggling quietly.

David Pecaut, co-founder of the festival with Toronto businessman, Tony Gagliano, has told CBC News he is suffering from colorectal cancer.

Organizers estimate more than a million people attended 10 days of Luminato events, from Cirque du Soleil at the waterfront to sold out musical and theatrical performances.

Luminato began as an idea Pecaut and Gagliano dreamed up over lunch. Together they convinced wealthy citizens, governments and corporate sponsors to fund Luminato and made it into one of the biggest arts festivals in the world.

"Number three definitely feels like Luminato has reached a new level — it can walk and talk now," Pecaut said proudly from his Bay Street office. He is chief executive of venture capital firm iFormation Group.

'I have to pace myself'

Pecaut said he's trying to stay positive about beating cancer and living one day at a time.

"I have to pace myself so I try to pick my spots and Luminato was so special for me this year because every day I could get to one or two things that meant a tonne to me and I felt it was an incredible high the whole time," he told CBC News.

Last Wednesday, he spent six hours at the hospital getting chemotherapy, then showed up at Massey Hall for a concert. He stood on the sidewalk, smiling and shaking hands with people.

Pecaut has been an unabashed Toronto booster, and has served as chair of the Toronto City Summit Alliance, a coalition of civic leaders, as well as contributing to youth, tourism and arts initiatives.

Earlier this year, he worked with the federal government to create the Canada Prize.

Pecaut recently stepped down as chair of the capital fund-raising campaign for the Bell Lightbox, the new headquarters of the Toronto International Film Festival.

But he said he's looking ahead to next year's Luminato.

"When thoughtful people work together in an honest and passionate way I think incredible things are possible," he said.

With files from CBC's Margo Kelly