 During his career he was an occasional exhibitor at the Royal Academy, the Suffolk Street, and other galleries.On his election in 1849 as member of the New Society of Painters in Water-colours—now the Royal Institute of Painters in Water Colours—he exhibited mainly there, altogether 100 pictures.Weir was a natural history artist and provided some of the illustrations for the Rev John George Wood's "Illustrated Natural History" (1853), served as chief illustrator for Charles St John's "Wild Sports and Natural History of the Highlands", and designed all of the illustrations for George Fyler Townsend's "Three Hundred Æsop's Fables" (1867).