Rainey was elected a member if the Royal Institute of Painters in Water Colours on 6 April 1891, and a member of the Royal Institute of Oil Painters on 25 November 1981. Rainey won medals for watercolours both the 1893 World's Columbian Exposition in Chicago and the 1900 Paris Exhibition. Rainey was still exhibiting in the 1930s, even though by now he has moved on to the retired list of the Royal Institute of Painters in Water Colours, being an honorary member from 1930.