born in Mastisiw, Poland, of Ukrainian parents, and arrived in the United States at New York City on November 25, 1909, under the name Michal Tkacz.
Tkach had long been active in the Communist Party of the United States (CPUSA) and was editor of the Ukrainian Daily News, the leading Ukrainian Communist newspaper in the U.S. As early as 1923, under the name M. Nastivsky, Tkach was an organization member of the Society for Technical Aid to Soviet Russia.
Tkach supervised a small network of American communists working as agents of the Soviet Union.
Tkach was investigated under the Internal Security Act by the FBI New York Field Division, which considered him to be a key figure in Communist subversion .
Tkach's cover name as assigned by Soviet intelligence and deciphered in Venona project transcripts is PERCH.