Born in Glasgow, Gibson became a supporter of home rule for Scotland through his membership of the Young Scots' Society, an affiliate of the Liberal Party.
He left the group in 1924 in opposition to its support of John Maclean, and instead joined the Scots National League.
He quickly became the group's leading figure, and ensured that it became the core of the National Party of Scotland, which he founded in 1928.
Gibson became increasingly involved in the civil service, and was out of Scottish nationalist politics until after World War II.
He rejoined the SNP in the late 1940s, working with Robert McIntyre and Arthur Donaldson, and was party president from around 1950 until 1958, remaining active into the 1960s.