"I'm truly humbled to be stepping into the footsteps of the legendary Pat Sajak," Seacrest posted on Instagram and Twitter.
Seacrest paid homage to Sajak and longtime co-host Vanna White and said he looked forward to "spinning the wheel and working alongside the great Vanna White."
Sony Pictures Television, the studio behind the show, said in a statement that "Wheel of Fortune" reaches 20 million unique viewers on average each week, the largest weekly television audience across syndication, broadcast and streaming.
Sony said Seacrest signed a "multi-year agreement" but did not specify how many years it would last.
The studio called Seacrest "one of the most nationally recognized voices in media today" after having hosted TV shows "American Idol" and "Live with Kelly and Ryan" and his own morning radio show.
"Many people probably don't know this but one of my first jobs was hosting a little game show called 'Click for Merv Griffin' 25 years ago so this is truly a full circle moment for me and I'm grateful to Sony for the opportunity," Seacrest said in the Sony statement.
Sajak, 76, took to Twitter earlier this month to announce his plan to retire after 41 seasons.
"I've decided that our 41st season, which begins in September, will be my last. It's been a wonderful ride, and I'll have more to say in the coming months," he wrote.
He ranks as the longest-serving host of any U.S. TV game show, surpassing the 35 years Bob Barker presided over "The Price is Right" on CBS or the 37 years Alex Trebek starred on "Jeopardy!"
Sajak and White won a Daytime Emmy for outstanding game show host three times out of a total of 19 nominations.
(Reporting by Danielle Broadway; Editing by Mary Milliken and Rosalba O'Brien)
By Danielle Broadway
