Young is best known for his work on Disney Channel's "The Famous Jett Jackson" and now appears on TNT's "Rizzoli & Isles."
TMZ said his body was discovered when he didn't show up to work Monday morning.
"It is with great sadness that I announce that Lee Thompson Young tragically took his own life this morning," said a statement from the actor's publicist. "Lee was more than just a brilliant young actor, he was a wonderful and gentle soul who will be truly missed."
"Everyone at 'Rizzoli & Isles' is devastated by the news of the passing of Lee Thompson Young," said a joint statement from TNT, Warner Bros. and "Rizzoli & Isles" executive producer Janet Tamaro.
"We are beyond heartbroken at the loss of this sweet, gentle, good-hearted, intelligent man," the statement said. "He was truly a member of our family. Lee will be cherished and remembered by all who knew and loved him, both on- and off-screen, for his positive energy, infectious smile and soulful grace. We send our deepest condolences and thoughts to his family, to his friends and, most especially, to his beloved mother."
His film credits include "Akeelah and the Bee" and "Friday Night Lights."