During the interim between St. Petersburg and Prague, he taught at the Kamianets Gymnasium (1918–1919), helped organize the Architectural Institute in Kyiv (1918-1919) and served as director of the construction department of the Podolia Governorate.

In Prague, he worked on his doctoral degree, taught at the art-school "Studio" (1923-1945), and served as a lecturer of the history of art at the Ukrainian Higher Pedagogical Institute (1923-1933).

A postwar refugee in Germany, in 1949 he emigrated to the United States where he continued to teach at the Ukrainian Technical Institute in New York City.

In addition to teaching, Sichynskyi worked as an architect designing churches, schools, and many private and public buildings in Ukraine, Slovakia, Brazil, Canada, and the United States.

He is the author of works on Ukrainian art, culture, architecture, engraving and printing, industry, and foreign sources on the history of Ukraine.