Leif Erlend Johannessen is a Norwegian chess player who earned the title of International Master in 1999 at the age of 16 and the Grandmaster title in 2002 at age 19. He was Norway's second Grandmaster after Simen Agdestein.
Born in Oslo, on May 14, 1980, he began his competitive chess career in 1991. His competition wins include the Norwegian Junior Chess Championship in 1995 and 1998, the Norwegian Chess Championship in 2002, and the Nordic Chess Championship in 2004. A decade later, he won the Norwegian Chess Championships again in 2014. A member of the Oslo Schakselskap chess club, Johannessen has represented Norway multiple times in the Chess Olympiad, with his debut in 2000.
Apart from his chess career, Johannessen studied medicine at the University of Oslo in 2006. He obtained his medical degree in 2013 and started working as a doctor the same year.