Carolina Sandgren is educated at Musikhögskolan and Operahögskolan in Stockholm and has sung in performances at Ystadoperan, Drottningholmsteatern, Studioteatern in Malmö and Malmö Musikteater. Her breakthrough came in 1993 as Nannetta in Falstaff (with Ingvar Wixell in the title role) at Stora Teatern in Gothenburg, where she also sang Gilda in Rigoletto the following year, also together with Ingvar Wixell.
In 1994 Carolina Sandgren joined the Göteborg Opera and her roles include Den blinda poetissan in Aniara, the Chambermaid Adèle in Die Fledermaus, which was also shown on TV, Zerlina in Don Giovanni, Fiordiligi in Cosi fan tutte, Countess Folleville in Il Viaggio a Reims, Antonia in Les Contes d'Hoffmann, Valencienne in The Merry Widow, which was also shown on TV, The Rag Doll in The Doll Doctor, Sister Constance in Les Dialogues des Carmelites, Oscar in Gustaf III, Un Ballo in Maschera and Donna Elvira in Don Giovanni.
Furthermore she has performed in a number of concerts at the Göteborg Opera. Carolina Sandgren has guested the opera in Weimar as Constanze in Mozart's Die Entführung aus dem Serail and is a frequent guest at concerts and festivals in Sweden as well as in radio and TV.