For many years, Karlsson worked mainly in oil and acrylic, but in more conventional sized formats. He became increasingly eager for larger renderings, but found it difficult to maintain the intensity and tension of the smaller paintings in large format. Several years ago, he solved the problem when he adopted the technique of using pastel chalk to make sketches that he could later render in oil or acrylic. He continues to work in all three media.
All of his works are untitled. Karlsson explains: "I feel that my work, in Abstract Expressionism style, should come fresh to the viewers, without the corrupting influence of the written word. By not using titles, I hope to liberate the viewers, to free them to participate with me in the creation, and to use their imaginations. Then, viewers can respond directly to the results and appreciate, or reject them without interference."
Karlsson was born in 1933 in Reykjavik, where he began his art studies.
At age 20, he came to the United States, where he later joined the International Monetary Fund in Washington, D.C., and became the Art Director for 30 years, with overall responsibility for the design of its internal and external publications.
In addition to his art studies in Iceland, he has studied at Washington's Corcoran School of Art, and also briefly at Mexico City College.
Karlsson's fascination with design has found expression in postage stamps. In 1961, he and an associate won a design competition sponsored by the United Nations Postal Administration for a stamp commemorating the International Monetary Fund. A few years later, he won a European competition for a stamp design sponsored by the Council of European Post and Telecommunications, and sixteen European countries circulated the stamp. In 1968, the United States Postal Service issued his design of a 10-cent commemorative stamp, marking the 50th anniversary of the U.S. Air Mail Service.
Karlsson has had several one-man shows in the United States; Reykjavik; Iceland; and Seville, Spain; and his paintings have been in a number of exhibitions in Iceland and the United States. He has been profiled and interviewed on local television shows, newspapers, and several prestigious art magazines, such as: International Artist (global), élan (Washington, D.C. Metropolitan Area), Hûs og Híbyli, (Iceland), and Mannlif (Iceland), and other works have been featured in a number of other exhibitions in Iceland and the United States.