During the Polish–Ukrainian War, the regiment fought to open the route to the besieged Lviv, capturing Horodok and later participating in the battles for Sambir, Drohobych, and Stanyslaviv, as well as actions along the Dniester and Zbruch rivers.

The regiment also participated in the victorious battle of Baboszewo in August 1920 and later took part in heavy fighting near Rohatyn and Vyshnivets during the advance toward Lviv.

[1] On 1 November 1918, the Governing Council and Garrison Command were created in Przemyśl to begin organizing Polish military forces and administration.

[5] The regiment gained its first combat experience during clashes with Ukrainian forces from 9 to 11 November 1918 in the Zasań district of Przemyśl.

[10] From June 28, the regiment fought along the Zbruch river, and in July 1919, it was transferred to the Volhynian front, where it battled Ukrainian units.

[12] The 37th Infantry Regiment secured the railway junction and other designated areas, then fortified its position, remaining in reserve until Kyiv was taken.

[12] A week later, it was transported to the Ratmirovicze station and subordinated to the commander of the 14th Infantry Division for planned operations near Bobruisk.

[12] Under pressure from the Soviets, particularly Semyon Budyonny's 1st Cavalry Army, the 2nd Battalion, acting as a rear guard, was encircled and destroyed.

[14] To prevent a potential Soviet offensive, the 4th Infantry Division, including the 37th Regiment, was transferred to the Chodorów area.

On 7 September 1920, the regiment engaged in intense battles with Soviet units threatening the Lviv–Chodorów railway line, capturing Knihynicze, Nowosielce, and Okrześnice.

Reinforced with three marching companies on September 13, the regiment, as part of the 4th Infantry Division, pursued the enemy to Vyshnivets.

[22] The barracks were cramped and lacked many basic facilities, including a sewage system, exercise grounds, proper storage, and a shooting range, which was only 100 meters long.

[22] Amid social tensions, the regiment was stationed in Warsaw from October to December 1923 (at the former Russian warehouses in Powązki), performing guard duties.

[23] On the afternoon of 13 May 1926, battalions I and II arrived in Warsaw by train and engaged in combat with government forces in Mokotów and the city center.

[27] On 26 June 1933, during a ceremony at the Piaski sports field in Kutno, President Ignacy Mościcki presented the regiment with a new banner, funded by the citizens of the Łęczyca Land.

The banner's godparents were the Łódź Voivode Aleksander Hauke-Nowak [pl] and Mrs. Maria Pajdakowa, wife of the Łęczyca County Starosta Zygmunt Pajdak.

[29] During the Battle of the Bzura, near Iłów, the standard was handed over for safekeeping to a local farmer, and its whereabouts have remained unknown since then.

[28] On 22 December 1928, the Minister of Military Affairs, Marshal Józef Piłsudski, approved the design and regulations for the commemorative insignia of the 37th Infantry Regiment.

[30] The insignia, measuring 43x43 mm, is in the shape of the Virtuti Militari Cross, with the arms enameled in navy blue.

[31] Further details on the soldiers' biographies can be accessed through resources provided by the Ministry of Culture and National Heritage[39] and the Katyn Museum.