Guðmundur Arnlaugsson was also known as a chess tournament arbiter from the early 1970s. In 1972, he became a FIDE International Arbiter. In 1981, he was one of the arbiters in Anatoly Karpov and Viktor Korchnoi World Chess Championship title match. Guðmundur Arnlaugsson has also been a chess commentator and promoter on Iceland radio and television.