Sepuloni first entered Parliament after the 2008 general election as a List member, becoming New Zealand's first MP of Tongan descent.
She is the MP for Kelston and has been New Zealand's Minister for Social Development since 2017.
She is also Minister for ACC and Minister for Arts, Culture and Heritage.
She was also previously the Minister for Disability Issues, but last year passed that portfolio to colleague Poto Williams.
Born and raised in Waitara, Taranaki, Sepuloni moved to Auckland in 1996.
She graduated from the Auckland College of Education with a Diploma in Teaching (Primary), before going on to the University of Auckland and earning a Bachelor of Education. She also holds a Postgraduate Diploma in Education.
Her father was a Samoan-Tongan migrant freezing worker and unionist. Her mother was Pākehā from a farming background. The MP is the middle child of three daughters.
Before entering Parliament, she worked in the tertiary sector as a literacy educator, a student mentor adviser, an equity manager, and a Pacific health research project manager.
On social media, the new Deputy PM describes herself as "a mother, a daughter of a migrant, Government Minister & NZ Labour MP for Kelston".
She has previously spoken of her love of poetry, and not just because she is married to poet Daren Kamali. She also writes poetry that she says "will never see the light of day".
"My husband likes to say that I'm creative as well, and I quietly write poetry that I only share with him," she said in an interview with Stuff last year.
"It's funny because I don't know if poetry ever comes from a happy place. It's always when I'm in a bad mood. It's quite therapeutic, I've found. But no one needs to see that."
Sepuloni, 46, is the mother of two boys. In the throes of lockdown in 2021, the minister went viral when one of her sons interrupted a live interview she was doing from home. The incident got the nation laughing and generated a lot of discussion about the challenges for parents trying to work from home during the Covid-19 pandemic.
Sepuloni said today she had told most of her family - including her sons - that she was up for the role of deputy PM, and they were all proud and excited for her.