Bartley Robilliard Pragnell received a diverse and accomplished art education, studying at several institutions across North America. He began his formal training at the Winnipeg School of Art where he studied with L. L. FitzGerald and was awarded the Mundell Prize Scholarship. He continued at the Banff School of Fine Arts, studying under Bernard Middleton and H.G. Glyde. Pragnell also trained under W.P. Weston and Jock MacDonald at the Department of Education in Victoria. In the early 1950s, Pragnell studied with the influential modernist Hans Hofmann in New York (circa 1952), followed by a summer course at the Chicago Art Institute. 

Born and raised in Saskatchewan, Pragnell ended up playing a pivotal role in arts education in the province. He was the founding Head of the Art Department at Moose Jaw’s Technical High School and served as the general art supervisor for all public and technical schools and colleges in Moose Jaw from 1932 to 1939.

Following his service as a public relations artist in the Royal Canadian Air Force during World War II, Pragnell resumed his teaching and artistic career, working in Winnipeg, Vermont, and California between 1949 and 1958. During his time in Winnipeg, he served as principal of the Winnipeg School of Art. Later, in Lethbridge, Alberta, he was appointed Director and Art Instructor at the Lethbridge Art Centre and also taught in the Lethbridge Sketch Club and local schools.

In 1963, Pragnell joined the faculty of the University of Alberta. He is credited with bringing a deep understanding of modernist art to his teaching, influencing a generation of Alberta artists. His own work reflects this influence—marked by abstracted spaces, bold use of colour, and monumental forms.

Pragnell was actively involved in numerous art organizations throughout his career. He was a member of the Winnipeg Sketch Club (1928–29), the Art Association of Saskatoon (1937), the Saskatchewan Provincial Art Association (1938), the Moose Jaw Sketch Club (1939), and the Royal Canadian Academy of Art (1939).

Pragnell passed away in Calgary, Alberta in 1966.