The division fought with distinction in the North African Campaign of World War II, notably during the Siege of Tobruk.

The main base of the brigade was established in Homs and the new unit instantly entered the ranks of the French Armée du Levant.

As a unit specializing in mountain warfare, the brigade was thought of as a Polish addition to Allied plans for landings in the Balkans.

Although new recruits arrived on a daily basis (mostly evacuated from Poland through Romania, Hungary, Greece and Yugoslavia), the brigade did not reach the planned numbers of 208 officers and 6840 soldiers and NCOs.

After the capitulation of France and the annulment of all of its pacts with Poland and the United Kingdom, the commander of the Armée du Levant General Eugène Mittelhauser decided to support the new Vichy government of Philippe Pétain, and Sikorski ordered the Poles to leave French territory.

On 30 April 1941, during the offensive of Erwin Rommel's Afrika Korps, the brigade was moved near to the front at the fort of Mersa Matruh, where it spent the next 10 weeks strengthening defensive positions.

Due to their impact on the battle, the Polish soldiers were awarded the prestigious title of the Rats of Tobruk by their Australian comrades in arms.

There it was joined by the Polish forces of General Władysław Anders evacuated from the Soviet Union and was reformed into the 3rd Carpathian Rifle Division.