Following his marriage to Helene Clara Welke on 13 October 1908, Lacey became increasingly involved in the trade union movement and was employed as the
Australian Workers' Union organiser at the smelter from 1916 to 1922. His high profile in the smelters led to his election to Port Pirie Municipal Council in 1920, a position he held until 1922 when he successfully stood as the Labor candidate for the Federal
Division of Grey against the incumbent
Alexander Poynton, a former Labor member who left the party over
conscription in
World War I. At this time, the Labor Party was split into three factions; Official Labor,
Premiers' Plan Labor and
Lang Labor, who all had different plans on combating the Depression. Lacey was leader of Official Labor, the largest Labor faction following the election, and became
Leader of the Opposition. As leader, Lacey advocated nationalising the banks and greater support for the unemployed. Regarded as "an affable people's man", he also played a leading role in reuniting the three factions in 1934 and remained Labor leader until 1938 when he stepped aside to become deputy leader under
Robert Richards. ==Death==