Stoltenberg participated in protest rallies against the U.S. war in Vietnam in the 1970s.[170] In 2011, Stoltenberg said "We sang the chorus, 'Singing Norway, Norway out of Nato.' It was a hit."[170]
In 2001, Stoltenberg crashed his Labour Party-owned car into a parked car; he then left the premises without leaving a note with his name or number; the damages cost 8000 Norwegian kronerto repair.[171]
In 2002, Stoltenberg admitted to having used hashish (cannabis) in his youth.[172] He therefore asked the Ministry of Justice and Public Security to evaluate his impartiality in the upcoming government response to the report on drugs by the Stoltenberg Commission, headed by his father, Thorvald Stoltenberg.[173]
In 2011 Stoltenberg got a 380,000 kroner boat as a birthday gift from the Norwegian Labour Party and the Norwegian Confederation of Trade Unions; the givers also paid the tax for the gift which led to criticism.[174][175]
I like the controversies section of his Wikipedia.