Alan Caswell Collier was born in Toronto, Ontario, in 1911. He expressed an early interest in art, he attended the Ontario College of Art where he studied under J.E.H MacDonald, Franklin Carmichael and others from 1929–1933.
In 1934 he traveled across Canada by train, followed by further studies in New York, while working as a miner during the summers.
On his return to New York in the fall of 1939 he became an advertising artist. After the war he resumed his career as an advertising artist in Toronto but did more painting and less commercial work. His experience in mining led him to begin working on paintings of underground mining during the early 1950's.
In 1955, Collier joined the staff of the Ontario College of Art where he taught advertising art.
In 1956, Collier made a three-month sketching trip to western Canada, he conitnued these trips every summer exploring parts of Canada. His paintings explored the many landscapes and activities that occured throughout Canada, such as fishing, his work during this time was exceptional and increased his popularity as an artist.
In 1963 Collier was awarded an eight-painting commission by Standard Oil of New Jersey, to depict the landscapes along the Trans-Canada Highway.
In 1967 he retired from Ontario College of Art to devote himself full time to his painting.
In 1971, a retrospective exhibition of his paintings and drawings from 1935 to 1970 was organized by the Robert McLaughlin Gallery, Oshawa, and then traveled to a number of Ontario galleries.
Collier also received a number of large mural commissions and for two weeks of each year during1984 and 1985 he sketched in the High Arctic as guest of the Polar Continental Shelf Project.
Collier exhibited widely and was a member of the Ontario Society of Artists beginning in 1952, and acted as President from 1958–1961. He was also a member of The Royal Canadian Academy as an associate in 1956 and became a member in1960.
He is represented in numerous public collections including, but not limited to, The National Gallery of Canada, The Art Gallery of Ontario, The Art Museum of London, The McLaughlin Gallery and The Tom Thomson Gallery.
Collier died in 1990.