[1][2] The regiment began forming in Vilnius, although in a covert manner, because the occupying German authorities hampered the formation of the Lithuanian Army.

[7] At the time, the regiment was divided into two battalions, with the first one, led by the officer Ignas Musteikis [lt], being composed of two infantry and one machine gun companies, while the remaining second battalion under officer Pranas Tamašauskas had just three infantry companies, that were not fully formed.

[7] The 1st Infantry Regiment fought in the Battle of Alytus [lt] from 12 to 15 February, but suffered its first defeat there and had to retreat.

[9] On April 25, the 1st Infantry Regiment included 57 officers, 21 military officials, and 1,640 soldiers.

[11] From 30 October 1919, the regiment's patron was the Grand Duke of Lithuania Gediminas.