He then taught mathematics at the high school level until 1937, when he obtained a faculty position at Charles University. When the German army invaded Czechoslovakia in 1938, Wolf obtained an invitation to visit the Mittag-Leffler Institute in Sweden; he remained in Sweden as part of the underground resistance to the Germans until 1941 before emigrating to the United States. He taught at Macalester College for a year, and then joined the faculty of the University of California, Berkeley in 1942.
He taught mathematics at the high school level until 1937, when he secured a faculty position at Charles University. When the German army invaded Czechoslovakia in 1938, Wolf was invited to visit the Mittag-Leffler Institute in Sweden; he remained in Sweden as part of the underground resistance against the Germans until 1941 before emigrating to the United States. He taught at Macalester College for a year, and then joined the faculty of the University of California, Berkeley in 1942.