McGarrell studied at Indiania University and Skowhegan School of Painting and Sculpture. He received an M.A. from the University of California, Los Angeles, California, in 1955, and then attended the State Academy of Fine Arts in Stuttgart from 1955-1956 with a Fulbright Grant for study in Germany. Among McGarrell's honors was a Guggenheim Fellowship in 1964 and two grants from the National Endowment for the Arts in 1967 and 1985. In 1970 he was elected Correspondent Member of the Academie des Beaux-Arts de L'Institut de France.
During his career, McGarrell has had over seventy solo exhibitions in the United States and in Europe. Several of the most notable were at the Portland Museum of Art in 1959 and 1963, Galerie Claude Bernard, Paris in 1967, 1970, and 1974, Bedford House, London in 1973, the St. Louis Art Museum in 1985, and at the Weatherspoon Art Gallery, University of North Carolina, Greensboro in 1990. McGarrell has regularly shown his paintings at Allan Frumkin Gallery since 1961. In addition, he has been included in Annual Exhibitions at the Whitney Museum of American Art, New York several times as well as at the Carnegie Institute, Pittsburgh, and in the exhibition "New Images of Man" at the Museum of Modern Art, New York in 1959. McGarrell's work can be found in the collections of the Metropolitan Museum of Art, New York, the Whitney Museum of American Art, New York, the Art Institute of Chicago, and the Hirshorn Museum and Sculpture Garden, Washington, D.C. McGarrell resides in St. Louis, Missouri and is represented by Frumkin/Adams Gallery, New York.
