[2] During this period, Wills became interested in syndicalism, and joined the Industrial Syndicalist Education League.
He became one of its most prominent speakers, travelling the country to address meetings, in particular during the London building workers' strike of 1914.
Later that year, he was a founder of the Building Workers' Industrial Union (BWIU), and was elected as its first general secretary.
This enabled him to win election as general secretary of the National Union of Corporation Workers in 1921, defeating Manny Shinwell, Chuter Ede, John Allen, Henry Bye and D. G. Stephens.
He immediately arranged for the union's head office to move to Bermondsey, and spent much of the decade campaigning against the contracting out of council services, and for the maintenance of existing levels of pay.