Complex sentence: He did not give names of Communist sympathizers, but he repudiated the organizations he had belonged to in the 1930s and 1940s and his own name was cleared, but he only received smaller roles and even those less frequently.
Split into simpler sentences: He did not give names of Communist sympathizers, but he repudiated the organizations he had belonged to in the 1930s and 1940s. His own name was cleared, but in the aftermath his career noticeably suffered, as he was offered smaller roles and those less frequently.