Roy Jacobsen grew up in a suburb of Oslo located in the Groruddalen valley. He held a number of occupations, even subsequent to his debut as a novelist in 1982. Since 1990 he has been a full-time author. During the years 1979 - 1986 he lived at his mother's homestead at Solfjellsjøen in the municipality Dønna in the Northern Norwegian county Nordland, and both the background of his mother as well as his own upbringing in Groruddalen were central themes of his breakthrough novel Seierherrene from 1991. This novel has described perhaps more directly than any other Norwegian work of fiction to the Norwegian public a phenomenon known in Norwegian culture as "the great class journey" – the upward motion through social strata experienced by large segments of the Norwegian population during a few generations in the 20th century. From the perspective of one family and spanning two generations the living conditions of the common man in Norway during the past 80 years is depicted, showing the tremendous pace with which an agrarian and proletarian society with its inherently rigid framework was transformed into a post-industrial, technological education and welfare society with a plethora of opportunities, however also presenting a newly created sense of identity for many of its citizens. Having proved himself in this fashion, Jacobsen became a natural choice as the biographer of Trygve Bratteli, the former Labour Party prime minister (1995).

He is a member of the Norwegian Academy for Language and Literature.