Magner was born in Stettin, Germany (now Szczecin, Poland); his father was a Lutheran director of a shipping line and his mother a Jewish concert pianist.
He acted in the Hamburg Chamber Theatre from the age of 18 and replaced the general director of the company when he left for fear of the Nazis, despite his protest that he was himself Jewish.
[1][2][3] In 1936 Magner emigrated to the United States, settling in Chicago, where a Prague friend, Kurt Herbert Adler, was doing theatre work.
His work included pioneering shows like Studio One, The Goldbergs, Lamp Unto My Feet, and Robert Montgomery Presents, and he hired a young Studs Terkel.
[5] He preferred classics; other examples were Georg Büchner's Woyzeck, Ben Jonson's Volpone, Jean Paul Sartre's The Condemned of Altona, Somerset Maugham's The Sacred Flame, and Athol Fugard's Blood Knot.