The baby, named Benjamin, was born at a hospital in Florida on Tuesday evening weighing more than 8 lbs (3.6 kg), according to a statement from Travolta's publicist.
"John, Kelly and their daughter Ella Bleu are ecstatic and very happy about the newest member of the family. Both mother and baby are healthy and doing beautifully," the statement said.
Jett, the first child of Travolta, 56, and Preston, 48, died of a seizure in January 2009 while the family was on vacation in the Bahamas. Travolta confirmed after the death that Jett was autistic.
The "Pulp Fiction" and "Grease" star and his actress wife spent a year out of the public spotlight grieving for Jett. The family was also the victim of an alleged $25 million extortion plot over the death that ended in a mistrial for those accused.
Travolta was back on the red carpet in January to promote his comedy adventure movie "From Paris with Love" and Preston appeared in the Miley Cyrus movie "The Last Song" in April.
