[4] His father was Khaim Movshevich[1] (Yefim Moiseyevich) Fridlyand (1860–1945); his mother was Rokhlya Shevakhovna[1] (Rakhil Savelyevna) (1880–1969).

During the First World War, his family fled the advancing German armies and returned to Kyiv, where he pursued legal studies.

From 1920 to 1921, Yefimov designed posters and brochures for the communist organization Agitprop, finally moving to Moscow in 1922 after his brother, who worked as an editor for Pravda, offered him a job drawing political cartoons.

His artistic talent, directed mainly against the West, gained him prominence, and his work started appearing in such titles as Izvestia, Krokodil and Ogoniok, a magazine founded by his brother Mikhail Koltsov (1898–1940).

The year 1924 saw the publication of his first book, Political Cartoons (Russian: Политические карикатуры, Politicheskiye Karikatury), which included a foreword by Leon Trotsky.

[6] In 1937 Boris Yefimov covered the Show Trials and drew cartoons against people like Nikolai Bukharin and Leon Trotsky.

After his death he left one son, Yefimov Mikhail Borisovitch (born in 1929), a grandson, and two great grandchildren.