He produced "soft-pencil" drawings of Mars in 1877, which were widely known.
Shortly after drawing them, he was the first to suggest that canals on Mars were an optical illusion.
In 1880 he was called to Balmoral and taught art to some members of the Royal family including Queen Victoria.
He was founding member of the British Astronomical Association (BAA) and its president from 1897–1898.
Green married Elizabeth Goold in 1847.
Their daughter, Anne Goold Green, married English landscape painter Laurence George Bomford.
A crater on Mars was named in his honor.