Byrne was born on May 24, 1933 in Chicago, Illinois. She studied at DePaul University. She was married to William Byrne from 1956 until his death in 1959. Then she was married to Jay McMullen from 1978 until his death in 1992. She had a daughter, Kathy by William Byrne. William Bryne died in an airplane accident. She was so far the only female mayor of Chicago.