Lane's body was found at the Comfort Inn Hotel in Woodland Hills, Calif. No cause of death has been determined.
Lane, born John Kennedy Oswald, joined the rock group, which also included Erik Turner, Josh Lewis, Jerry Dixon, and Steven Sweet, in 1986. It would, over the years, have a revolving lineup. Lane left the band in 2004, but rejoined briefly in 2008, before leaving again. Warrant's biggest hit was the double-entendre-fest "Cherry Pie" in 1990.
Bret Michaels, who was in lookalike band Poison, tweeted about the death late Thursday night. "We'd like to offer our deepest condolences to the family of Jani Lane regarding their loss. Respectfully, Bret and all at [Michaels Entertainment Group Inc.]."
Lane, who appeared on VH1's Celebrity Fit Club in 2005, had a history with alcohol-related arrests. In 2009 he pleaded no contests to misdemeanor DUI and was put on probation for three years. In 2010, he was arrested for another alcohol-related incident and jailed for 120 days.