Henry Irvin "Shorty" Shope was born on his father's ranch, "Circle Arrow," in Boulder, Jefferson County, Montana on May 11, 1900 to Ira and Emilie Shope. Irvin Shope contracted polio when he was nine years old, and when he was twelve, his father died. Following his father's death, his mother moved their family to Missoula, Montana. While living in Missoula, Irvin met and was mentored by the artist Edgar S. Paxson. Following high school, Shope attended the Portland Art Academy and Reed College, later attending Montana State University (now University of Montana - Missoula). While he was attending university in Missoula, he would cowboy in the spring and summer and enroll in school in the winters. He cowboyed from 1919 - 1930, taking up easel painting during this time. Shope sold his first painting to the Diamond Cattle Company in Texas in 1920 and was exhibiting his paintings by 1925. In 1928, Shope's friend Will James, an artist, helped him secure an illustrating commission. He sold his first major oil painting in 1930, right before he returned to college in 1931. He graduated with a degree in fine art and history in 1932. Irvin "Shorty" Shope married Erva Vivian Love on June 23, 1932, and the couple moved to Los Angeles, California that same year. Irvin and Erva Shope had four children: Joyce, Jane, Judith, and Richard.

In 1934, the Shopes returned to Montana where Irvin worked for the Montana Highway Department from 1934-1945 as a graphic artist in the advertising section, producing many widely distributed maps, brochures and posters. While working for the department, Shope also produced a comic strip titled "Rusty Rawlins Cowboy" from 1934-1935. Following the Montana Highway Department, Shope worked as the chief graphic artist for the Montana Power Company. Shope's usual subjects in his paintings were cowboys, the Blackfeet, mountains, and deserts, with all of his works having a distinctly western look. In 1937, Shope was adopted by the Blackfeet and given the name "Moquea Stumock" meaning "Wolf Bull-Man the Size of Wolf with Big Heart like Buffalo." In 1938, Shope spent three months in New York City as a pupil of Harvey Dunn. In 1939, he constructed their family home at 1337 Ninth Avenue in Helena, Montana. From 1959-1960 Shope was commissioned to produce 11 paintings for the Northwest Paper Company featuring Mounties, Native Americans, ranchers and cattle.

Over his career, Shope created numerous illustrations for books and magazine covers, painted murals for the University of Montana, the Montana Highway Department and several commercial institutions in Helena and produced numerous works on canvas and paper. His artist's signature included the logo/brand for his father's ranch, the circle arrow. Irvin "Shorty" Shope was voted into the National Cowboy Association in Oklahoma City in 1966 and became the first Montana artist to be exhibited in the Cowboy Hall of Fame. He was honored as a University of Montana Distinguished Alumni in 1972. Irvin "Shorty" Shope died in 1977 while visiting his daughter in Massachusetts.