During the strikes in 1917, he represented the interest of waterfront workers in collective bargaining, and by then was regarded as the leader of all waterfront workers. He became even more popular when he helped to secure increase wages for them.
In the 1917-1918 period, Critchlow led a petition for an 8-hour day. He was pressured by the Chamber of Commerce to withdraw his name from the petition, after all the other petitioners were forced to do so, but he obstinately refused. He was immediately fired from his job and blacklisted from obtaining employment, and he had to depend on assistance from close friends for sustenance.
Critchlow was employed on a full time basis by the union, and he never stopped being a spokesman for the workers, and publicised their grievances and demanded improved working conditions and better wages for them.