In 1931, Emerson joined Engelhard, Pollak, Pitcher & Stern (earlier Simpson, Warren & Cardozo and later Engelhard, Pollak, Pitcher, Stern & Clarke). Emerson worked primarily for Carl Stern and Walter Pollak. Colleagues there included Arthur H. Goldberg. With law firm colleague Walter Pollak served the defense team that helped appeal convictions of the "Scottsboro Boys" in Powell v. Alabama (1932).
