Born in Istanbul to Chiot parents who left the island due to the Massacre of Chios, Syggros was one of the founders of the Bank of Constantinople along with Stephanos Skouloudis.

Buying land from the widow of Dimitrios Rallis, Syggros engaged the well-known Athenian architect Nikolaos Soutsos who built his home based on plans by the German Ernst Ziller, across from the Royal Palace.

[2] In 1873, he profited from the stock market scandal that followed the Lavreotika dispute, having previously raised the price of the Greek Company of Lavrion Mines stocks by maintaining or spreading false rumors about the existence of gold reserves in the mines.

[3] In 1882, he founded the Privileged Bank of Epirothessaly in Volos to help the economy of the newly annexed Greek territories of Epiros and Thessaly.

[5] Syggros also became involved in numerous works of public philanthropy, including building an avenue from the Royal Palace to the bay at Palaio Faliro (named after him today, Andrea Syggrou Avenue) and he was responsible for completing the Corinth Canal, one of the great feats of engineering in Greece, in 1893.