B. C. Vladeck cultivated the friendship of William Green, president of the American Federation of Labor (AFL), and hoped, with reason, that Green would welcome the JLC as a trusted advisory body on Jewish affairs. As president of the JLC, Vladeck addressed the 1934 convention of the AFL, presenting the Nazi persecution of Jews as an integral part of a general assault on labor rights and political liberty. In response the AFL created a Labor Chest to aid the victims of fascism; in coming years, the Chest funded a host of JLC-inspired educational and aid projects.

The JLC handled much of the editorial work for the Labor Chest News Service and produced many Labor Chest pamphlets. The Committee also organized a number of mass meetings in New York City under Labor Chest auspices -- including a solemn commemoration of the anniversary of the 1934 Austrian workers uprising against fascism.

The JLC worked with other Jewish organizations engaged in anti-Nazi work, though it sometimes chafed at the more cautious instincts of its partners. For instance, one of the JLC's chief concerns was to build support for a boycott of Nazi goods. At the urging of Vladeck and Jewish union leaders, the AFL came out in favor of a boycott at its 1933 convention. The American Jewish Congress, under the direction of Rabbi Stephen Wise, had been a pioneer in the advocacy of the boycott strategy; but Rabbi Wise, unlike the JLC, declined to join in boycott activity not conducted by Jews. The American Jewish Committee, B'nai B'rith, and other mainstream Jewish organizations hung back from the boycott, fearing either a backlash against Jews in Germany or an upsurge of anti-Semitism in America if Jews adopted such high-profile methods as picketing and public appeals. In February 1936 the JLC joined with the American Jewish Congress to form the Joint Boycott Council. The Council's work had some effect in the area of consumer goods, eventually enlisting Macy's, Gimbel's, and other major retailers in the boycott. There were also demonstrations on the shop floor by workers protesting the use of German supplies and equipment.

While the JLC urged unified action, it also pursued an independent anti-Nazi campaign on many fronts. For example, when the American Olympics Committee declined to heed widespread protests against United States participation in the Berlin Olympics of 1936, the JLC held a World Labor Athletic Carnival (also known as the Counter-Olympics) at Randall's Island in New York City during August 1936. Dozens of teams representing New York union locals competed, and the main events featured outstanding amateur athletes from across the country. Governor Herbert Lehman presented the prizes. The Carnival received extensive nationwide press coverage, and the JLC repeated the event in the summer of 1937.