The division, supported by Battalion Kłobuck of the National Defense, defended 40-kilometer long section of the Polish–German border, between the towns of Lubliniec and Krzepice, north of which units of Łódź Army were stationed.
Due to quick advance of the panzer units of the Wehrmacht, in the night of 1/2 September 1939, the division retreated from its positions near Kłobuck and Truskolasy, and manned main defence line around Częstochowa.
The advance, supported by divisional artillery, was at first successful, but after some time, German machine gun fire together with tanks halted the Poles.
After the Sikorski–Mayski agreement of 1941, in February of the following year the 7th Division was recreated in the Soviet Union as part of the Anders Army/Polish Armed Forces in the East.
At the same time one of the units of the Polish People's Army formed under guidance of the Soviet Union received the same number (see pl:7 Łużycka Dywizja Piechoty).
Insufficiently equipped and trained, the unit was attached to the Second Army and dispatched to the front near Rothernburg, where it stormed the Lusatian Neisse river with heavy casualties.
After the war ended, the PPA 7th Infantry Division, under the control of the Second Army, was assigned to protect the Mużakowa – Kopaczów section of the western border.