Langer was a Czechoslovak writer, playwright, legionnaire during World War I in Ukraine and Russia and military doctor. His family was Jewish but did not practise the faith.
He was a friend with the popular writers Jaroslav Hašek and Karel Čapek. In 1930, Karel Čapek persuaded František Langer to take over the dramaturgy at Prague Divadlo na Vinohradech (Vinohrady Theatre), where he stayed until 1935.
After the Munich Agreement in 1938, Langer was drafted back into the army with the rank of colonel. At the beginning of July 1939, Langer decided to emigrate to France, where the Czechoslovak Army was formed abroad. In 1940 he went to the UK. Returning to Czechoslovakia he arrived in May 1945 in liberated Prague. He started to work in the health care in Czechoslovak army. In 1947 he was appointed a national artist. After the Communist coup in February 1948, he ceased to be active, his books were not banned, but were published exceptionally.