Born near Tacoma, Washington, Lars grew up with nature and art playing a prominent role in his life. Some of his earliest drawings and paintings were made to raise money for mission projects at his local church. His mother was a high school art teacher and his father an amateur naturalist and door-to-door religous book salesman. In 1965 he moved with his family to British Columbia, Canada and lived in Victoria, British Columbia for most of his youth.

From 1974 to 1979 Justinen took fine arts and pre-med from Walla Walla University in Washington State. In 1980 he committed to an art career and returned to British Columbia and spent 5 years working as a gallery artist, painting landscapes and wildlife paintings for solo and group exhibitions. During this time he had his first experiences working with digital media, taking his first digital illustration course in 1982 at Capilano College near Vancouver, British Columbia.

From 1985 to 1991 he worked as an in-house illustrator for Pacific Press Publishing Association in Nampa, Idaho and was also actively involved in freelance projects, being represented by Jerry Leff and Associates in New York as a book and magazine illustrator. During this period he painted illustrations for national book and magazine publishers like New Yorker magazine, McGraw Hill, Scholastic Books, Focus on the Family, Public Television, Pebble Beach Golf Club, and Avon Books, winning several national awards for his work in publications such as PRINT, Communication Arts, The Society of Illustrators, and Japan Creative Annual.

In 1991 he and his wife, Kim, started Justinen Creative Group, expanding into digital media which took him into the world of creative direction and writing, and included producing large animated online training websites for the US Forest Service, the American Youth Soccer Organization, and the US Department of the Interior. During this period the Justinens had two children, Hannah and Stephen. In 2000 he and his wife launched which has grown into the world's largest online stock licensing site for Christian and religious art. In 2003 Justinen Creative Group started a branch of their company focused on custom photo portraits for the funeral industry with

Today he, his wife, Kim Justinen, - also an artist - live in Surrey, British Columbia, while managing their business in Nampa, Idaho, near the state capital of Boise. They often summer in Quatsino, British Columbia where they lived from 2002 to 2009 while their children were in middle school. Their son is a bioengineer and their daugther is completing her degree in animation from Southern Adventist University.

Lars' views on art can be summed up by these thoughts:

"... God created man in His own image." Genesis 1:27 There is something uniquely fulfilling in creating a work of art. Most everyone finds pleasure in making something and enjoying the work of others. The act of creating something is, in many ways, a spiritual experience. “In the beginning, God created...” Genesis 1:1