Mia's father Elliott Deighton Mottley was a barrister who sat in the House of Assembly for a relatively short time, vacating the seat to become consul-general in New York.

He married Mia's mother Santa Amor Tappin in December 1964, three years after being called to the Bar, and was elected to represent Bridgetown in May 1969.

[9] Mottley first entered Barbadian politics in 1991, when she lost an election race in St. Michael North East against Leroy Brathwaite (a defeat of fewer than 200 votes).

During that time, she served on numerous Parliamentary Joint Select Committees on areas including Praedial Larceny and Domestic Violence.

She is also credited with being the visionary behind the Education Sector Enhancement Programme, popularly known as "EduTech", which aims to increase the number of young people contributing to the island's sustainable social, cultural and economic development.

She held the chairmanship of a number of key Cabinet sub-committees, notably on Telecommunications Reform and on oversight of the administrative and legislative initiatives to prepare Barbados for the advent of the Caribbean Single Market and Economy.

She promised the people that the Barbados Labour Party would be a strong and unified Opposition that would fight for the rights of all citizens in the country.

In the February 2013 general election, the BLP was narrowly defeated, obtaining 14 seats against 16 for the Democratic Labour Party (DLP).

[12] In the 24 May 2018 general election, the BLP won the biggest majority government in Barbadian history, winning more than 70 per cent of the popular vote and all 30 seats in the legislature.

[15] A week after the elections, Joseph Atherley, MP for St. Michael West, left the BLP to become the House of Assembly's sole opposition member, citing concerns about democracy.

[citation needed] A week later, following the election, on 5 June 2018 Barbados failed to fulfil its obligation to pay the 26th coupon on Eurobonds maturing in 2035.

A University of the West Indies (UWI) poll in Barbados found that, although only a minority wanted to retain the Barbadian monarch as head of state, most objected to the lack of consultation.

[29] Mottley addressed the United Nations General Assembly in New York on 24 September 2021 with a short speech to support UN Secretary-General António Guterres' warnings that the world is moving in the wrong direction.

She threw away her original script and instead gave a passionate post in which she called for global, moral leadership in the fight against climate change, economic and technological inequality, racism and unfair distribution of COVID-19 vaccines.

[35] In November 2022, Mottley delivered the Nelson Mandela Annual Lecture, with the theme being "Social Bonding and Decolonisation in the Context of the Climate Crisis: Perspectives from the Global South".

[36] Mottley addressed the United Nations General Assembly again in September 2024, succeeding Israeli Prime Minister Benjamin Netanyahu as speaker.

[43] In May 2022, Mottley was featured on the cover of TIME magazine, the first Barbadian to do so, and was named one of "The 100 Most Influential People of 2022",[44][45] in recognition of her outspoken advocacy for addressing climate change.