Born in 1899 in what was then part of the Austrian Empire, Tomášek was one of the six children of a schoolteacher who died when he was still a boy. After completing his schooling and military service, he studied at the seminary in Olomouc and was ordained on 7 May 1922. He taught religion in schools. Later he also taught at the Cyril and Methodius theological faculty, where he obtained a doctorate in 1938. Soon after, the Nazi occupation led to the closure of the Czech universities and Tomášek returned to schoolteaching. After the war, Tomasek again taught in the faculty and also obtained a second doctorate.