Clare Coghill has been chosen to succeed Chris Robbins as leader of Waltham Forest Council.
The cabinet member for economic growth was backed to take the helm at the town hall by 30 out of 40 of her fellow Labour councillors in a private meeting of the group on Thursday night.
It follows the resignation of Councillor Robbins, who announced last month that he would stand down in May after leading the council for eight years.
In a statement Cllr Coghill said: “It’s a great privilege to be elected as leader of the Labour group. The chance to serve our borough and build a community that is open, tolerant and fair is one that I relish.
“The council I lead will prioritise smashing down barriers for our young people, supporting vulnerable residents and building good quality social housing.
“We must unite to tackle the problems of hate crime, intolerance and ignorance that mean that even in 2017, people attack one another for being different – whether that’s gender, sexuality, race or faith.
“Over the past six years – under drastic financial constraints – Waltham Forest has made tremendous progress. As Leader I will look to maintain this progress and continue the improvement to services that residents expect.
“I look forward to working with residents and colleagues to make this vision a reality”
Cllr Coghill defeated her colleagues Nadeem Ali and Gerry Lyons in Thursday’s ballot of Labour councillors. She will become the first woman to lead Waltham Forest Council.