In 1977, Andersen was crowned Miss Hawaii USA 1978 and earned the right to represent Hawaii at Miss USA 1978 in Charleston, South Carolina. She went on to win the title, becoming the third woman from Hawaii to be crowned Miss USA. As Miss USA, Andersen represented the United States at Miss Universe 1978 in Acapulco, Mexico. Despite receiving the highest scores in interview and swimsuit, in addition to having the highest averaged semifinal score, Andersen placed as the first runner-up to Margaret Gardiner of South Africa; this was the best result for an American delegate at Miss Universe since Amanda Jones placed as the first runner-up at Miss Universe 1973.[2]