[2] Claussen made her debut in La favorita in Stockholm on 19 January 1903, and remained with the Royal Swedish Opera for nine seasons.

She sang at Covent Garden and in Paris, and appeared as Ortrud in Lohengrin in Chicago in 1913.

[6][7] She toured in Scandinavia in 1920,[8] was decorated by the King of Sweden,[9] and gave a recital at New York's Aeolian Hall on her return to the United States.

She was usually seen in Wagnerian roles, including Brunnhilde in Die Walküre, and Kundry in Parsifal, both in 1922.

[13] Fellow singer Rosa Ponselle also considered her Italian opera roles impressive, saying Claussen was "the ideal Amneris.