He was pleased with the win, particularly after missing out on a council seat by just 77 votes at the local government elections in October 2013.
"I was absolutely gutted when that happened, so I told myself it was no big deal if I didn't win this time.
"I was surprised that I won by so much. I thought it would be a close race," Mr Granville said.
Winning the council seat is not the only change in Mr Granville's life.
After being the breakfast host at MoreFM for the past five years, he will finish at the end of the month.
"I've bought Take It Easy Tours, and me and my mate Jimmy Elliott are going to run it together." Born and raised in Wanganui, Mr Granville said he wanted to gain a seat on the council to represent Wanganui's everyday Kiwis.
"That's who I am. I see myself as the servant of the ordinary people in Wanganui, and I want to try and help them as much as I can. "I have a lot to learn but I'm not afraid to ask questions."
Since his election, Mr Granville had spoken with Mayor Annette Main, and some of his fellow councillors.
"Annette and I get on well. We're going to have a proper catch-up during the week."
Mr Granville paid tribute to his fellow candidates and thanked them for putting their names forward for the by-election. He also thanked his family and friends for their "wonderful support".
"To everyone that supported me, I really appreciate it."