Policitian, who was one of the Red Clydesiders. Born the son of a labourer in the East End of Glasgow, Kirkwood was educated at Parkhead Public School and trained as an engineer. He worked at William Beardmore's Parkhead Forge, the Mount Vernon Steel Works and at John Brown & Company shipyard in Clydebank. A committed socialist, he became a shop steward at the Parkhead Forge in 1910 and was an organiser of the strike there in 1916, in his role as treasurer of the Clyde Workers' Committee, an organisation chaired by Willie Gallacher (1881 - 1965), which had been formed to organise workers against Britain's entry into the First World War. He was tried under the Defence of the Realm Act, and 'expelled' to Edinburgh, along with Arthur MacManus (1889 - 1927) and Willie Gallacher. In 1919, he attempted to quell a violent demonstration in George Square in Glasgow, supporting the reduction of the working week to 40 hours, but was arrested by the police.
He went on to serve on Glasgow Town Council (representing Mile End) and was elected as Independent Labour Party Member of Parliament for the Dumbarton Burghs in 1922. He joined the Labour Party in 1932. He drew attention to the effect of the economic depression on Clydebank in the 1930s and influenced the decision to resume work on the Queen Mary, which gave the community vital work. On retiring from the House of Commons in 1951, he was raised to the peerage as Baron Kirkwood of Bearsden.
Kirkwood published his autobiography, My Life of Revolt, in 1935.