Former oil and gas executive Wayne Stewart has dropped out of Calgary's mayoral race, endorsing candidate Naheed Nenshi. (CBC)

Wayne Stewart ended his campaign for mayor on Thursday, throwing his support behind candidate Naheed Nenshi.

Stewart, a former oil and gas executive and advocate for the homeless, said in a news release that he ran for mayor not because he had a burning desire to hold the position, but because he wanted to make sure city hall "never again takes Calgarians for granted."

At a news conference, Stewart said he made the decision to drop out of the race mainly because of his poor results in recent polls.

"Well, we knew right from the start that I had an issue with name recognition," said Stewart. "I've learned an awful lot through this campaign. I was not as good a candidate when we started off. I made some personal stumbles, our campaign made some stumbles."

He said he has known Nenshi for some time and believes their priorities align. He said he would act as a volunteer mentor to Nenshi.

"Our offices are down the hall from one another at Mount Royal University, and we've got a history together and he's acted as a mentor for me for a long time," said Nenshi, appearing alongside Stewart at the conference. "So I'm thrilled he's going to be back in this role."

Stewart said he was courted for support by a number of other candidates. But his volunteers will be going to Nenshi.

Stewart thanked his supporters and those who had already voted for him in advanced polls.

Ald. Bob Hawkesworth quit the race on Wednesday and endorsed Barb Higgins.