Roos was born in 1808 to Thomas and Mary Roose of Bodgadfa, Amlwch on the Isle of Anglesey. Although no exact date of birth exists, he was christened on 30 April 1808. In 1858, at the National Eisteddfod at Llangollen, Roos' paintings The Death of Owen Glyndwr and The Death of Captain Wynn at Alma won the second place prize. Although based in Wales, he spent periods of time in London and frequently travelled in order to sustain his potrair work.
A popular portrait painter, several of his portraits are now held at the National Museum of Wales, including oils of preacher Christmas Evans, Thomas Charles, John Cox, and poet John Jones. The Museum also houses several mezzotints and lithograph portraits by him.
Paintings by Roos
- Lloyd, John Edward; Jenkins, R.T. (1958). The Dictionary of Welsh Biography, Down to 1940. Cardiff: William Lewis. p. 890.
- Welsh engravers National Library of Wales