Demaine was born at
Bradford, Yorkshire, to parents Joseph Demaine, cabinetmaker, and Elizabeth (née Halliwell). At around age 15, he went with his family to Uruguay and Argentina where he worked as a
printer, returning to England in 1879. He landed in
Queensland in March 1880 and began work as a
joiner for Fairlie & Sons and within two years had formed an Eight Hour Association and participated in a campaign to remove black labour from the sugar industry. Leaving Fairlie & Sons in 1890, he set about forming the General Labourers' Union, which was later absorbed into the
Australian Workers' Union and as Secretary of the Wide Bay and Burnett Branch of the Australian Labor Federation, he helped organize support for the shearers in the
1891 strike. In 1892, Demaine represented the Maryborough Workers' Political Organization at the first Labor-in-Politics convention before being elected to the central political executive in 1892–94. Along with
Charles McGhie, he founded the weekly newspaper
Alert which he edited until his death. In 1901 he once again attended the Labor-in-Politics convention and until 1938, every convention thereafter. Elected president of the central political executive in 1916, he held the role unopposed for the next 22 years. ==Political career==