Her secondary education came at Notre Dame Academy in Omaha, Nebraska, with vocal lessons added to her other classes.

[3] She studied piano and voice at Duchesne Academy of the Sacred Heart (Nebraska), where she became interested in jazz.

After beginning her career at the Blackstone Hotel in Omaha, she joined a United States Navy recruiting tour during World War II.

She was the first to record "When I Fall in Love", accompanied by the song's composer, Victor Young and his orchestra with lyrics by Edward Heyman, in April 1952.

In a 2010 newspaper article, King talked about Southern's shyness, saying she had "a paralyzing case of performance anxiety.