Þorgrímur Þráinsson was born in Reykjavík, January 8, 1959. He graduated from highschool in 1980 and studied French at Sorbonne in Paris 1983-1984. He worked as a journalist for the publishing house Fróði for a number of years, and was the editor of the Sportsmagazine and a assistant editor of the children's magazine, ABC. In 1996 Þorgrímur became the manager of Tobacco Control Task Force of Iceland. Þorgrímur played soccer with the Reykjavík soccer club Valur in the Icelandic premier league from 1979 to 1990 and was a captain for the last five seasons. Before he had played with the team Víkingur from the town Ólafsvík. During his soccer-carrier his team won the Icelandic championship three times, and the Icelandic cup two times. Þorgrímur played alltogether around 180 games in the premier league and 17 national games for Iceland. In addition he won the Icelandic cup in athletics with FH (Hafnafjörður Gymnastic Club), for javelin throw.
Þorgrímur has written a number of popular books for children and adolescents and his first book, Með fiðring í tánum (Fidgety Toes) from 1989, was a bestseller in its time. Þorgrímur received The Icelandic Children's Book Prize in 1997 for his book Margt býr í myrkrinu. His first novel for adults, Allt hold er hey, was published in 2004.
Þorgrímur Þráinsson is married and lives in Reykjavík.