Lars Mikkelsen was born in Gladsaxe, Denmark, as the first child of Bente Christiansen, an occupational health nurse, and Henning Mikkelsen, a bank clerk. Growing up in Copenhagen, Lars had a younger brother, Mads, who also became an actor. The family initially resided in the middle-class district of Østerbro before moving to the working-class district of Nørrebro.
During his childhood, Lars was an active child, playing handball and singing in the school choir. On New Year's Eve in 1985/86, he met his future wife, Anette Støvelbæk, and they have been together ever since, eventually getting married in October 1989.
After completing his education, Lars served his basic military service in the Kongelige Livgarde (Royal Guards) for nine months. However, he found the experience unsatisfying and decided to pursue a new path. He began studying biology but dropped out after a semester to focus on juggling, which he had discovered through Anette. Lars enrolled in a juggler school, where he learned various skills, including fire breathing, and later toured Europe with friends as traveling artists.
Two years into his juggling career, Lars met a children's circus, which introduced him to pantomime, street, and children's theater. At the age of 27, Lars decided to transition into acting and applied to the Statens Teaterskole (National Theatre School of Denmark) in Copenhagen, where he was accepted and studied from 1991 to 1995. Shortly after his graduation, he made his stage debut in the play "Dracula" at the Aalborg Theater.
Since his graduation, Lars has appeared in over 40 plays and has continued to work in film and television. His breakthrough role came in the successful Danish crime series "The Killing" (2007),playing the mayoral candidate Troels Hartmann. This led to international recognition and roles in productions such as the British series "Sherlock" (2010),the Russian president Viktor Petrov in the third season of "House of Cards" (2013),and a leading role in the international crime series "The Team" (2015). For his performances, Lars has received various nominations and awards.
Lars currently resides with his wife, Anette, and their two sons, Lue (born in 1995) and Thor (born in 2000),in the Copenhagen district of Vesterbro.