In 1811 he traveled to Norway and settled in Christiania where he taught at the School of Drawing (Norwegian Tegneskolen) in Christiania from 1819 to 1851. Flintoe represented the transition in Norwegian art from the early landscape paintings of the romantic era that came to flourish at the end of his career. He was a teacher for several of the leading national romantic artists including Johan Fredrik Eckersberg and Hans Gude.
Flintoe later returned to Denmark and died in Copenhagen on 27 January 1870. Flintoe is remembered for influencing the development of landscape painting in 19th century Norway at a time when interest in national romanticism was blossoming. He traveled widely in Norway himself, painting numerous landscapes and national costumes, all considered to be of high cultural importance.