[1] His father married in 1888 to his mother, who was widowed with five children at the time; Kozal had six siblings, including brother Wojciech, who participated in the Greater Poland Uprising and the Polish-Bolshevik War, in which he was killed at Grodno in 1920.

[1][2] On 1 June 1920 he was appointed as the administrator of the Saint Nicholas parish until 1923 and around this time collaborated with the Catholic Action movement and the Polish Red Cross.

Cardinal August Hlond – on 1 November 1927 – placed him in a leadership position at Gniezno in addition to serving as a theological and liturgical studies professor; he was appointed as the rector on 25 September 1929.

[2][3] The Gestapo arrested him and 44 other priests and seminarians on 7 November 1939, and he was tortured and jailed in his diocese; he was later moved to Lad before being sent to both Szczeglin and Berlin before the fatal transfer to Dachau, from which he would never again leave.

On 16 January 1940 he was relocated to a Cistercian convent turned camp for a brief imprisonment and suffered frostbite on his ears and nose during the cold in his transfer; he was there until 3 April 1941 when moved to Inowrocław.

Kozal never shirked from his duties and spent his time in imprisonment ministering to fellow prisoners despite extensive abuse he received from the guards at the camp.