Shadbolt received 11,590 votes, which put him well ahead of his closest challenger, Tom Conroy, on 6109.
Karen Arnold was third with 3193 votes.
Shadbolt said it was a "huge relief" to be re-elected as mayor, and he was incredibly grateful for his supporters, Fairfax reported.
"It's been the toughest campaign I've been involved with".
Mr Shadbolt’s first term was from 1993-1995. He was re-elected mayor in 1998 and has held the position since.