Henryk Dobrzański was born on 22 June 1897 in Jasło, Austria-Hungary to a Polish noble family (Coat of arms of Leliwa), of Henryk Dobrzański de Hubal and Maria Dobrzańska née Lubieniecka. In 1912 he joined the "Drużyny Strzeleckie", a Polish pro-independence youth organisation. When World War I broke out he volunteered to join Józef Piłsudski's Polish Legions. He served with distinction in the 2nd Regiment of Uhlans and participated in many battles such as Stawczany and Battle of Rarańcza. In 1918 after Poland regained its independence he joined the Polish Army.