As Grethe Clemmensen, she made her debut in 1955 with Malihini Hawaiians. Shortly after that she sang with the trio and orchestra of Jørn Grauengaard. Her initial releases were credited to her maiden name. She was married to Jørgen Ingmann from 1956 until their divorce in 1975. Performing as Grethe & Jørgen Ingmann they won the 1963 European Song Contest with "Dansevise". As a solo artist she had occasional pop success nationally. Half sister of producer, band leader Leif Pedersen.