In 1909, five years after joining the Zionist movement, he was named Secretary of the Zionist Federation of Germany (ZFfD) and in 1913 became the editor of the Zionist weekly Die Welt . Blumenfeld headed a group of young Zionist activists who, on the eve of World War I, radicalised the ZVfD, advocated emigration to Palestine as part of every Zionist's plans in life, and intensified the struggle with the Liberal German-Jewish establishment, foremost the Central Association (CV). Blumenfeld became president of the Zionist Federation of Germany in 1923 and held this position until he emigrated to Palestine in 1933.
