However, Zulauf managed to escape from captivity and cross the front lines to rejoin the Polish Legions.

After Poland was reestablished in 1918, Juliusz Zulauf returned to his hometown, where he joined the Polish Army and took part in the defence of Lwów during the Polish-Ukrainian War.

On May 11, 1919, he was given the command of the Polish 4th Legions Infantry Regiment and took part in the opening stages of the Polish-Bolshevik War.

He held that post until April 1930, when he was promoted to commanding officer of the prestigious Polish 2nd Legions Infantry Division stationed in Kielce.

From September 14, Zulauf commanded the eastern perimeter of Warsaw's defences, in the city's easternmost district, Praga.