PORTLAND — Michael Brennan was sworn in today as the city’s first elected mayor in 88 years.

Appearing relaxed and exuberant, Brennan thanked outgoing Mayor Nick Mavodones Jr. for helping him with the transition over the past month.

“I feel like we will be able to hit the ground running,” Brennan said.

The packed crowd at the City Council chambers gave Brennan an extended standing ovation after he was sworn in by City Clerk Katherine Jones.

Brennan will deliver his inaugural address at 6 p.m. tonight at the Ocean Gateway passenger terminal on the waterfront.

Prior to the ceremony, Mavodones urged the city’s elected officials to support the new mayor, explaining he will be under intense scrutiny in coming months.

“He’s going to do an incredibly good job for the city of Portland,” he told the crowd. “It’s not an easy job. There is going to be quite a spotlight for sure, particularly from the press. The city councilors and other elected officials need to be supportive. I really encourage and challenge the elected officials in the community to get behind the mayor.”

Mavodones had been an outspoken critic of the proposal by the Charter Commission to make the mayor’s post an elected, full-time job. He later ran for the office and was defeated, coming in third place in a field with 15 candidates.

For the past eight decades, the mayor was essentially the chairman of the council. The council chose a new mayor every year, usually giving the gavel to the most senior council member who had yet to serve in the post.

The post of elected mayor lacks executive power, and the city manager retains oversight over the city’s day-to-day operations.

Brennan said he sees his role as leading the debate on policy matters and building coalitions. The mandate he received from winning a high-profile, citywide election is expected to give him considerable influence over the City Council and the School Board.

During his campaign, Brennan said he would focus on job creation and improving the city’s school system.

Brennan received 8,971 votes in 13 rounds of ranked-choice voting. Ethan Strimling came in second with 7,138 votes, and Mavodones came in third with 4,075 votes.

More than 19,500 people cast votes in the mayor’s race, the first of its kind in Portland in 88 years.

Councilors Cheryl Leeman and John Coyne were also sworn into office today. Leeman, who has served on the council for nearly 27 years, won 71 percent of the vote to beat challenger Ezekiel Callanan.  Coyne ran unopposed.

During brief remarks following the ceremony, Brennan thanked outgoing Councilor Dory Waxman, whose seat was eliminated by the Charter Commission to make way for the position of elected mayor.

Brennan praised Waxman for her service to the city.

“The city of Portland cannot thank you enough for what you have done for the city,” he said to Waxman, who wept while the crowd gave her a standing ovation.