He was a leader in the 2010-11 student campaign that stopped tuition fee increases at Northern Irish universities.
[13] While working for Global Witness, McGibbon led a coalition of organisations that forced Prime Minister Boris Johnson to end the UK's multi-billion taxpayer finance for fossil fuel projects overseas in December 2020.
[15] By the 2021 United Nations Climate Change Conference in Glasgow, the campaign had produced a "domino effect," pushing 25 other countries, including the United States and Canada, to join the UK in phasing out public finance for overseas fossil fuel projects.
[16][17] McGibbon was the inaugural winner of the Spirit of Northern Ireland ‘Climate Hero’ award in 2021.
[18] McGibbon has written for The Guardian, The Independent, The Nation, The New Statesman, Reader’s Digest, The Times and others on politics, the environment and Northern Irish affairs.