In 1926, his family moved to Tula, Russia. Four years later, Semon worked at the Tula Arm Factory Palace of Culture Art Studio until 1934, during which time he graduated from middle school and trade school. Semon entered the Russian National Academy of Arts Institute in Leningrad. From 1934-37, he studied at the preparatory department of the Institute, until becoming a student from 1937-41. During this time, he participated in local, republican and national art exhibitions.
When the Great Patriotic War began, Rotnitski joined the military. One year later, he became a member of the Communist Party. In 1945, Rotnitski was demobilized to resume his education. In 1948, he completed his study at the I.E. Repin Institue. That same year, he joined the Leningrad Chapter of the Russian Artists Union.
For twelve years, Rotnitski taught at the Kazan Trade School of Arts, during which he was also director of the school. In 1953 he was elected a member of the Tatar Artists Union management , and in 1957, he was named Honorable Art Worker of Tatarstan.
In 1960, Rotnitski moved to Leningrad and became a teacher at the V.I.Mukhina Higher Trade School of Art and Industry in Leningrad in 1965 where he taught for 16 years. In 1970, he became a docent of the Painting Faculty.
Semon Rotnitski has held personal exhibitions at the Mukhina Higher Trade School of Art and Industry in Leningrad, 1981; the Summer Garden Coffee House in Leningrad in 1985; and in the Leningrad Artist Union in 1991.
"Truthful and deep penetration into the character is what I believe to be the artists main objective. The whole life is too short for it. It takes talent and hard work. As for the results, they will be evaluated by the contemporaries and descendants," say Rotnitski. The artist believes his duty is to "be able to see the beauty of nature and man and to communicate this beauty to the spectator."
Rotnitski's works are found in major museums in Moscow, Saint Petersburg, Samara, Kazan, Tver, Perm, Pskov, Kislovodsk, Krasnoyarsk, the Fleischer Museum and in private collections in the Soviet Union and the United States.