Leibowitz will oversee all aspects of the luxury line’s operations.
These responsibilities will include revenue management, deployment and itinerary planning, hotel operations, sales and marketing.
He will report to Stein Kruse, group chief executive of Holland America Group and Carnival UK.
Leibowitz joined Carnival Corp in 2013 as chief strategy officer. He was named senior vice-president of Cunard North America in December 2016.
Before joining Carnival Corp, he was a managing partner of the Miami office of consultancy firm McKinsey and Co.
He succeeds Rick Meadows, who retired earlier this year after 35 years with Carnival Corp.
"We are excited to welcome Josh into this new role on our senior leadership team, where he will bring extensive experience and knowledge that will further strengthen Seabourn’s position in the market," said Kruse.
"I am confident Josh will help carry Seabourn through the challenges currently facing the travel industry to build on its longstanding reputation as an ultra-luxury travel brand unlike any other, supported by a team of people whose everyday focus is on delivering the best."
Leibowitz added he was excited to get to work with Seabourn’s crew, its travel agent partners and guests. "Our main priority will be working together as we develop plans to resume operations and welcome our past and future guests onboard to create lasting travel memories."
