By 1885 Oscar was employed at D. H. Hutchison's Elite Photo Co., where he was responsible for the colouring and over-painting of photographic portraits, which was much in vogue at the time.

He was, with L. W. K. Wirth, James Laurence Watts, and Walter Jenner, in 1888 a founding member of the Queensland Art Society.

[7][8] In August 1894 an exhibition of oil portraits by Fristrom was mounted at the "Easel Clubroom" at Fritz and Bernard's Art Palace, 62 Rundle Street in Adelaide.

In 1904 a new Society of Artists was formed; meetings were held in Fristrom's studio in "Oakden Chambers", Queen Street.

He married Margaret Johnston of South Brisbane in July 1886; they had a daughter Olivia, a promising pianist, and a son.

Another brother, Tage Edward Friström, a member of the US Voluntary Infantry, was killed in 1898 fighting Spain in Manila.