In the years leading up to the outbreak of World War II, Kowalski was noted for his performances with Polskie Radio, the national broadcasting organization.
Performances he made on the radio were broadcast live across the country, and reached audiences in Germany, Czechoslovakia, Russia, and Lithuania.
Polyakin's approval helped his admittance to the Moscow Conservatory, where he continued his studies with Abram Yampolsky, a well-known violin teacher.
[3] Before returning to Poland, he embarked on a very successful concert tour in Czechoslovakia, and was compared by his reviewers to the most prominent violinists of the era.
After this period, he again moved to Israel, but the outbreak and aftermath of the Six-Day War convinced him and his family to emigrate to the United States.
In April 1971, he settled down in Providence, Rhode Island, and took up a position at the music department of Brown University as a violin instructor.
He continued to receive recognition for his talents in America, and on February 6, 1978, he was invited with his wife and other distinguished Americans of Polish descent to the White House by President Jimmy Carter.
[8] Kowalski died suddenly due to hemorrhage of the upper intestinal tract, at the age of 70, on January 24, 1982, in Providence, Rhode Island.
Both of his parents, Abram and Dora, his three sisters, Lonia, Genia, and Danusia, and his brother David were killed by German soldiers in Brest Litovsk in 1942, when the Jewish ghetto there was liquidated.