From 1930 to 1957, von Euler was married to Jane Sodenstierna. They had four children: Hans Leo, scientist administrator at the National Institutes of Health, Bethesda, Maryland, U.S.A.; Johan Christopher, anesthesiologist, Serafimer Hospital, Stockholm; Ursula Katarina, Ph.D., curator at The Royal Collections, The Royal Court, Stockholm, Sweden; and Marie Jane, Chemical Engineer, Melbourne, Australia. In 1958, von Euler married Countess Dagmar Cronstedt, a radio broadcaster who had during the Second World War worked at Radio Königsberg, broadcasting German propaganda to neutral Sweden.