Naomi Long said she was daunted and excited in equal measure after being elected the new leader of the Alliance Party.
Mrs Long's appointment at a special party council meeting in east Belfast was a foregone conclusion, given she was the only member to put her name forward to succeed retiring David Ford.
The former MP, who had served as deputy leader for 10 years, vowed to work hard to deliver electoral success for the cross-community party.
The East Belfast Assembly Member praised the "good grace and dedication" of outgoing Mr Ford as she gave an acceptance speech to 130 party members.
Former Stormont Justice minister Mr Ford has retired after 15 years at the head of the party.
"It's a huge honour but also a huge responsibility, daunting but exciting in equal measure," said Mrs Long as she thanked the party faithful for entrusting her to lead them.
One time Belfast city mayor said she wanted to engage with members and would-be members to help make the party the political home of those who want to build a "liberal and progressive future".
She said she wanted to celebrate the differences in Northern Ireland society.
"We have an important job to do in this society, offering a clear and ambitious alternative vision for the future," Mrs Long said.
"An aspirational vision of a society which is progressive, liberal, fair and open, in which rights are respected, talent is celebrated, creativity is nurtured and each person is valued.
"That is a vision which only a party which itself is progressive, liberal, fair and open, a party that has a diverse and vibrant membership, a party committed to offering hope for the future, not fear of it, can truly represent."
She added: "When it comes to difference, we have a choice - we can use it to divide people and make it a weakness or we can embrace and celebrate that diversity, and make it our strength. We in Alliance choose to celebrate it."
Mrs Long's was given a rapturous response after her election was confirmed.
Concluding her remarks, the new leader vowed to reach out to those disaffected with politics in Northern Ireland.
She said: "To young people, to new voters, to those living in communities where paramilitaries still exert control, to people for whom the terms of nationalism and unionism remind them of another generation's politics rather than our own, to people who are interested in politics but fed up with what so often passes for politics at Stormont, to people who look in despair at the rise of the right and the isolationism gripping international and national politics and want to be a voice for openness and inclusion, to people who may well share our values and vision but for whatever reason don't connect with the party right now - I want to hear your voices and work to make sure that together we can build this party into one that people who want to build a liberal and progressive future see as their home."