In 1980, Whitehorse earned her bachelor of arts degree in painting from the University of New Mexico in Albuquerque. She earned her masters of art degree in 1982, also from UNM, majoring in printmaking and minoring in art history.
Whitehorse's paintings draw upon a personal iconography, based on her reflections of her natural surroundings. She brings together Navajo cosmological perspectives with abstraction in her work. Whitehorse's work is deliberately apolitical. Her paintings are usually oil on paper, mounted on canvas. Her work is represented in public collections throughout North America, Europe, Japan, Uzbekistan and Morocco.