When aged 16, Carroll fund-raised with fellow activists to travel to
Edinburgh,
Scotland for the
Make Poverty History protest. He contested the
2011 Belfast West by-election—triggered by the resignation of
Gerry Adams—for the
People Before Profit, and won 7.6% of the vote. At the
2014 Belfast City Council election he gained one of the seven seats in the
Black Mountain electoral area from
Sinn Féin, coming third. Following his election, he said that he did not describe himself as a
nationalist or a
unionist, instead choosing to identify as a
socialist. He said: "There is a lot of anger in West Belfast at the minute over the situation at
Royal Victoria Hospital's
A&E, the privatisation of leisure centres and the Casement Park issues...residents have been trampled on". He contested Belfast West again at the
2015 general election, this time coming second, gaining 19.2% of the vote and reducing the Sinn Féin majority from 57.1% to 35.0%. After being elected a councillor, Carroll criticised the large pay rises that were given to councillors whilst other council staff suffered effective pay cuts, and campaigned against privatisation and cuts. He criticised Sinn Féin's "support for capitalism", and spoke against the "
sectarian nature" of politics in Northern Ireland. In August 2014 he said: "In Northern Ireland sectarianism is at the heart of the state. I don't accept that, but then again I don't accept the conservative right-wing state in the south". At the
2016 Assembly election he was elected an
MLA for
Belfast West, topping the poll on the first count and gaining a seat from
Rosie McCorley of Sinn Féin. He was re-elected at the
2017 election; however, his vote fell from 22.9% to 12.2% in the face of a 4% overall Sinn Féin vote increase that cost fellow People Before Profit MLA
Eamonn McCann and the
SDLP's
Alex Attwood their re-election bids. Carroll's support for
Brexit, in an area in which three-quarters of voters voted Remain, attracted criticism from Sinn Féin and pro-EU activists. Carroll stood in the
2019 general election and came in second place behind incumbent
Sinn Féin MP
Paul Maskey. Carroll defended the seat in the
2022 Northern Ireland Assembly election but with a reduced majority of 7.51% of first preference votes, down from 12.15% in 2017. == Electoral history ==