Karayianni was born Lela Minopoulou, in Limni, Euboea, in 1898. She initially used her own house and her husband's pharmacy to hide British soldiers and airmen during the World War II occupation of Greece by the Axis powers. She later organised the resistance movement "Bouboulina" whose aim was to gather information and pass it down to the Allies in the Middle East.
Karayianni was taken to SS headquarters on Merlin Street in Athens where she was tortured in order to reveal information about her resistance movement. She was taken to a concentration camp in Chaidari and later, on September 8, 1944, was executed at Dafni.
Her bust stands on Stournara Street, Athens.