She won the Norwegian national final Melodi Grand Prix 1987 in a very close regional vote, giving her the opportunity to compete for Norway at the Eurovision Song Contest 1987 with the song "Mitt liv" (My Life), written by Rolf Løvland and Hanne Krogh.
Gulbrandsen tried to represent Norway again in 1989, singing "Nærhet" (Closeness) at the Melodi Grand Prix, although was unplaced.
Her version of Jørn Hansen's "Med gullet for øyet" was the official song of the 1998 Winter Paralympics in Nagano, Japan.
In 2004, after more than ten years away from the Norwegian popular music scene, Kate made a musical comeback in country style with two new tracks reaching Norsktoppen, Norway's main pop chart.
In 2023, she returned to the Norwegian Melodi Grand Prix contest with her song "Tårer i Paradis" (Tears in Paradise).