Little had been sought after by Labour to run on the party ticket for mayor - up against incumbent Tory Whanau, who is running on the endorsement of the Green Party.
Six other contenders, including Whanau, have already announced they plan to run for the capital's top job.
The other five consist of current councillor Ray Chung, former councillor Rob Goulden, conservationist Kelvin Hastie, businessman Karl Tiefenbacher, and Wellington Live's Graham Bloxham.
Little said if he was elected, he would prioritise fixing the pipes, making public transport cheaper, investing in parks, swimming pools and libraries, and developing more housing.
He said Wellingtonians did not vote for asset sales or closing community facilities.
"My focus as mayor will be getting the best for Wellington. That means being able to work constructively with the government in the city's interests and it means standing up to the Beehive when needed."
Little - who is currently a consultant for a law firm in Wellington - left Parliament following Labour's 2023 election defeat after first entering politics in 2011.
He shot to the party leadership in 2014, but stood down just two months out from the 2017 election, making way for Jacinda Ardern, who went on to be prime minister.
During his time in government, Little held 12 ministerial portfolios - the most difficult of his tenure being Health Minister during the Covid-19 response years.
He was given the role by Ardern following the 2020 election and was the minister who oversaw the seismic overhaul of the sector, scrapping all 20 district health boards and replacing them with two new entities - Health New Zealand and the Māori Health Authority.
Other senior ministerial roles he held included: Minister for Treaty Negotiations, Defence, the Security Intelligence Service, Justice, and Immigration.
Whanau has previously said having several candidates for the mayoralty was good for democracy. "I also respect Andrew Little from my time at Parliament, especially when he stepped aside as leader for the Labour Party."
Little said he had submitted his nomination seeking the Wellington Labour Party's support for his mayoral campaign.
