He was editor of the newspaper Vilniaus aušra (1932–1939) and chairman of the Society of Saint Casimir for the Education and Care of Young People (1932–1937).
During World War II, he worked at the diocesan chancery of the Archdiocese of Vilnius and was selected by Archbishop Mečislovas Reinys as one of his successors.
His father was an enterprising farmer and managed to save and borrow enough money to buy about 98 hectares (240 acres) of land in Lapušiškė [lt] near Rimšė in 1897.
[1] Taškūnas started the paperwork to apply to the Saint Petersburg Roman Catholic Theological Academy in 1906, but was admitted only in 1911.
He joined a monastery of the Congregation of Marian Fathers of the Immaculate Conception in Marijampolė, but left after six weeks due to lack of calling.
After the death of Petras Kraujalis, Taškūnas was appointed as the instructor of the Lithuanian language at Vilnius Priest Seminary in September 1933.
Since Lithuania–Poland relations were tense due to the territorial dispute over Vilnius, activists faced repressions from the Polish authorities.
[1] In July 1932, Taškūnas was elected chairman of the Society of Saint Casimir for the Education and Care of Young People replacing priest Antanas Viskantas [lt].
[6] The society organized local chapters in towns and villages to promote the Lithuanian national identity and Catholicism.
In 1936, Polish authorities ramped up anti-Lithuanian activities and closed the vast majority of the local chapters of the Society of Saint Casimir.
[6] A month before the closure, society's headquarters and residences of its board members (including that of Taškūnas) was searched by the police.
[7] Taškūnas also contributed articles to other Lithuanian periodicals published in Vilnius (Kelias, Jaunimo draugas, Vilniaus rytojus) and in independent Lithuania (Mūsų laikraštis, Draugija, Šaltinis).
[1] During an air raid by the Soviet forces on the night of 23 March 1942, a bomb fell onto the clergy house of the Church of Saint Nicholas, Vilnius.
[2] Archbishop Mečislovas Reinys selected Edmundas Basys [lt], Taškūnas, and Juozapas Dubietis as his successors and administrators of the archdiocese.