After graduating the Minneapolis College of Art and Design in 1950, Robert moved to Arizona. He became an artist of Western scenes and native Americans. His specialty was the ancient culture of the Hopi and the Navajo. Robert and his wife Lola spent a lot of time on location. Lola wrote as Robert painted and researched. Robert taught art classes and private students.

His work was in galleries from New York, Texas, New Mexico and Arizona. His work appeared in Arizona Highways Magazine, Southwest Art and Western Art Digest.

They are exhibited by the San Diego Museum of Art, the Museum of Northern Arizona, and the William Penn Memorial Museum. He worked in advertising taught art at the Kachina School of Art in Phoenix.

Knudson summed up his ideas of painting light, "What I try to get in my paintings is the quality of light. Light defines drama and contrast. To me it parallels life, highlights many thoughts about principles of change, survival, eternality. Light sets the mood, the dynamic to any moment on the landscape and suggests a grand theme"...Artist Statement, courtesy Sue Willoughby from "Custom Showcase", 1989.