Donaldson debuted on stage when he was seven years old, performing in Uncle Brown's Leather Couch at the Stora Theatre in Norrköping, Sweden.

Donaldson moved from theatrical productions to singing, first with the Duff Opera Company and then performing in a concert tour with Emma Cecilia Thursby.

In 1903, Donaldson created the title role in The Prince of Pilsen with the Tivoli Opera Company in San Francisco.

After Ireland, he returned briefly to Sweden, appearing in operettas at Oscarsteatern and making two Swedish films (one as director) before going back to America.

Upon his return to the U.S., he worked again with Sidney Olcott in films such as A Mother of Men (1914), The Irish in America (1915), shot in 1914 in Ireland, The Moth and the Flame (1915), and The Ghost of Twisted Oaks (1915).