Many of its founders had been involved in the resistance to the First World War: its first Secretary, Herbert Runham Brown, had spent two and a half years in a British prison as a conscientious objector.

Two years later, in 1923, Tracy Dickinson Mygatt, Frances M. Witherspoon, Jessie Wallace Hughan, and John Haynes Holmes founded the War Resisters League in the United States.

Notable members include Dutch anarchist Bart de Ligt, Quaker Richard Gregg and Tolstoyan Valentin Bulgakov.

WRI attracted some of the world's best pacifist thinkers and activists, amongst them George Lansbury, Mahatma Gandhi, Bertrand Russell, Bayard Rustin, Martin Niemoeller and Danilo Dolci.

[3] One of the leaders of the Norwegian branch of WRI (FmK), Olaf Kullmann, was arrested by the German Occupiers for his pacifist agitation; he was sent to the Sachsenhausen concentration camp, where he died in 1942.