The paper tells about a prominent Galician public fgure K.M. Valnitskiy (1889-1937 (?)), a leaders of Russian (Russophile) movement in Austro-Hungary and Poland. Valnitskiy was an advocate of the Russian national democratism and a leader of the Galician-Russian socialist coterie. Today his name is practically forgotten; however, he played a great role in history as an activist of both Russian and Ukrainian movements, a deputy of Polish Sejm and a prisoner of the Czarist jail, the infamous Austrian concentration camp Thalerhof as well as Polish and Soviet camps. For the frst time ever in national and foreign historiography the article analyses Valnitskiy's biography and views. The authors place special emphasis on his opinions of the Russian revolution of 1917, Civil War, armed intervention and Soviet-Polish war. Through the lens of documentation in Russian and Ukrainian archives, K.M. Valnitskiy's abundant journalistic heritage (articles in Lviv newspapers "Prikarpatskaya Rus'", "Rus'", "Zhizn'", "Volya naroda") as well as other Russian, Ukrainian, and Polish sources, the authors offer insights into the contemporary historical studies concerning the specificity of the Galician-Russian movement of the early 20th century.