Shubart was born on 21 October 1873 in Liegnitz, then part of the German Empire. He studied classical philology and philosophy at the Universities of Tübingen, Halle, Berlin and Breslau, earning his PhD at the latter institution in 1897. In 1900 he obtained his habilitation in ancient history at Berlin, becoming an associate professor in 1912. From 1931 to 1937 he was an honorary professor in Berlin, later serving as a professor of ancient history at the University of Leipzig (1948–52).
On 17 December 1928, he married Gertrud Schubart-Fikentscher, who later became a professor of law at the University of Halle. Shubart died in Halle on 9 August 1960.
- Das Buch bei den Griechen und Römern, 1907 – The book of Greeks and Romans.
- Elephantine-Papyri (with Otto Rubensohn and Wilhelm Spiegelberg), 1907 – Elephantine papyri.
- Papyri graecae berolinenses, 1911 – Greek papyri in Berlin [collections].
- Einführung in die papyruskunde, 1918 – Introduction to papyrus studies.
- Papyri und Ostraka der Ptolemäerzeit, 1922 – Papyri and ostracon of the Ptolemaic Era.
- Palaeographie, 1925 – Palaeography.
- Justinian und Theodora, 1936 – Justinian and Theodora.