The reception after Mayor Nancy R. Rossi’s swearing-in ceremony was still going on in the West Haven High School cafeteria afternoon when Rossi expressed her intention to head straight from there to her new City Hall office.

To get to work. On a Sunday — within hours of taking the oath of office.

So much for savoring the moment.

But as Rossi, 59, West Haven’s 12th — and first female — mayor, told hundreds of West Haveners who packed the high school auditorium a few minutes earlier, she’s got lots of work to do.

“Today, West Haven begins a new path — a path that takes us to balanced budgets” and a new outlook, Rossi said during an inaugural address that also expressed her intention to work together with others who have been on opposite sides of West Haven’s often-shifting political fences.

“My fellow elected officials who are here onstage, I pledge my support and commit to working with all of you for all the residents of West Haven,” she said.

Rossi, who defeated incumbent Mayor Ed O'Brien on Nov. 7, added later, “I believe, if we work together — no matter what our faction or party affiliation — we can achieve real change” and steer the city toward success.

Also taking the oath of office Sunday were City Clerk Deborah Collins — heading into her 10th term — City Treasurer Mike Last, Tax Collector Dorothy Chambrelli, 13 City Council members, four Board of Education members and three members of the Board of Assessment Appeals.

Council members sworn in included Bridgette Hoskie, D-1; Nick Ruickoldt, D-2; Aaron Charney, D-3; Mitchell Gallignano, D-4; Robbin Watt Hamilton, D-5; Peter Massaro, D-6; Portia Bias, D-7; Tracy Morrissey, D-8; Sean Ronan, D-9; Louise Martone, D-10; Richard DePalma, R-at-large, David Forsyth, D-at-large, and Ron Quagliani, D-at-large.

Board of Education members included Lauren Ann Aceto, Jim Morrissey, Rosa Richardson and Rosemary Russo. Board of Assessment Appeals members included Ralph Biondi, Joseph Palmucci and Richard Standish.

Rossi and all but two of the elected officials were sworn in by former Judge of Probate E. Michael Heffernan. Collins was sworn in by Corporation Counsel Vin Amendola, and Chambrelli was sworn in by Superior Court Judge Trial Referee Edward J. Dolan.

Among those attending were U.S. Sen. Richard Blumenthal, who was keynote speaker, former Mayor John Picard, New Haven Mayor Toni Harp and North Haven First Selectman Michael Freda.

Also attending were state Sen. Gayle Slossberg, D-Milford, state Reps. Charles Ferraro, R-West Haven, Dorinda Borer, D-West Haven, and Michael DiMassa, D-West Haven, Notre Dame High School President Robert Curis, Counsul General Ömür Budak of the Turkish Consulate in Boston and the president of the Turkish-American Religious Foundation.

Borer, the master of ceremonies, took time at one point “to acknowledge our first female mayor,” telling Rossi, “On behalf of all of our women here ... thank you.”

The quest for balanced budgets will begin with an immediate freeze on all nonessential hiring — not including first responders — and a spending freeze that will require approval of the mayor’s office in advance of all expenditures, Rossi said.

“Also, something is gong to be done with overtime,” she said.