[3] In August 1939, as World War II loomed, Kaplansky returned to Białystok in an unsuccessful attempt to persuade his father and brothers to come to Canada.
He boarded SS Athenia to cross the Atlantic on his return trip in September 1939 and was one of the survivors when it became the first British ship to be sunk by the Germans after Britain declared war.
[1][3] Kaplansky persuaded the Canadian division of the United Steel Workers of America to introduce a resolution at the 1947 Canadian Congress of Labour convention calling for "vigorous action" on the part of the CCL and its affiliated unions in "the fight for full equality for all peoples, regardless of race, colour, creed, or national origin.
"[5] Kaplansky and the JLC were thus able to organize Joint Labour Committees to Combat Racial Intolerance with the CCL and the TLC in Montreal, Toronto, Windsor, Winnipeg and Vancouver[5] that fought against discrimination against minorities including Jews, Black Canadians, French Canadians and Roman Catholics and actively investigated and exposed complaints of discriminatory practices.
[3][5] His work helped bring about the Ontario Fair Employment Practices Act of 1951 that banned racial discrimination in hiring and influenced legislation across the country.
[7] In 1947, Kaplansky and Moishe Lewis spearheaded "The Tailors Project" by the Workmen's Circle and Jewish Labour Committee to bring European Jewish refugees to Montreal to work in the needle trades[10] They were able to do this through the federal government's "bulk-labour" program that allowed labour-intensive industries to bring European displaced persons to Canada, in order to fill those jobs.