3rd Rock from the Sun (1996)

"There's a new family in town. They're not from another city... They're from another planet."

The high commander of an alien expedition lands on Earth -- what he considers to be the least-important planet -- in human form as Dick Solomon. Along for the ride are his alien compatriots Harry, Sally and Tommy -- who is the eldest of the group but is now angrily trapped in a teen's body.