Smoira was born in 1888 in Königsberg, in the German Empire[1] to Leiser and Perel, Hasidic immigrants from Russia.

His future wife, Esther Horovitz from Minsk, was a relative of Zalman Shazar.

After the war, he organized Hebrew courses in Berlin and later received his doctorate in jurisprudence from the University of Giessen[1] as well as an M.A.

He was a partner of Pinchas Rosen, who later became the Israeli Justice Minister, and was associated with Mapai.

His daughter, Michal, married Supreme Court judge Haim Cohn.