In 1861 he received his law degree from the Ionian University with a scholarship and continued his studies at the Sorbonne in Paris.

He also improved drastically the condition of the Navy by promoting better training and establishing many naval academies and schools.

With the aid of professor Papamarkos, Theotokis prepared and submitted to Parliament progressive legislation for the improvement of education in Greece.

He provided assistance for the Macedonian Struggle and is noted for his calm and deliberate foreign policy in the tense period just prior to the Balkan Wars (1912–1913).

The second mistake was Theotokis's refusal to mediate between King Constantine I of Greece and Prime Minister Eleftherios Venizelos during 1915–1916, a disagreement that eventually grew to become the National Schism.