After gymnasium school coll studies in Příbram, he studied botany at the Charles University in Prague, and graduated in 1906. In 1916 he was named as professor of botany. Domin specialised in phytogeography, geobotany and plant taxonomy. He became a member at the Czechoslovak Academy of Sciences, published many scientific works and founded a botany institute at the university. The Domin scale, a commonly used means of classifying a standard area by the number of plant species found in that area, is named after him.
In the academic year 1933-34 he was rector of Charles University and was one of the participants of a struggle for ancient academic insignia between the Czech and German universities of Prague (the insigniáda) that resulted in street-fights and looting. From 1935 to 1939 he was a member of parliament; after the Munich Agreement, he co-founded a traditionalist political movement (Akce národní obrody).