After the German invasion of Poland, he started to create underground structures of the peasant movement. Initially, he was in favor of including peasants in the Union of Armed Struggle. However, the reluctant attitude of the leadership of this formation to the People's Party led to the decision to create a separate organization. Already at the beginning of 1940 he made such a proposal to the Central Leadership of the People's Movement.
In August 1940, the Peasant Guard was created (in the spring of 1941 it changed its name to Peasant Battalions). Franciszek Kamiński was appointed commander of this formation and held this function until the end of World War II.
In 1942, during the ethnic cleansing of Zamojszczyzna by Nazi Germany organized speeches by peasant guerrilla units against the occupation forces.[2] In March 1943, he merged the Peasant Battalions with the Home Army. In 1944, he became a member of the Home Army Headquarters. He participated in the Warsaw Uprising. After his fall, together with other peasant movement activists, he found himself in Podkowa Leśna.
The grave of general Franciszek Kamiński at the Powązki Military Cemetery in Warsaw
In May 1949, he was expelled from the Polish People's Party because he did not want to make a self-criticism. On 21 July 1950, he was arrested by the Stalinist authorities. In December 1951, by a verdict of the Military Court, he was sentenced to 12 years in prison and forfeiture of all property. He was in prison in Warsaw.
He was released as a result of an amnesty in April 1956.[4] In October the same year, the College of Judges of the Supreme Military Court in Warsaw overruled his judgment and discontinued the proceedings. After being released, he started working as an official. He retired in 1973. He no longer undertook active political activities.
From 1957 to 1959 he presided and managed the work of the Historical Commission of Peasant Battalions established at the United People's Party.[4] In 1970 he initiated the independent celebrations of the 50th anniversary of the Battle of Warsaw.