The four-time Grand Slam winner will join fellow WTA legends Martina Navratilova and Arantxa Sanchez-Vicario in the role, and will be in Singapore during the Oct 22-29 event.
She was unveiled in her new role on the sidelines of the Porsche Tennis Grand Prix in Stuttgart on Tuesday (April 25), where the ticket sales were also launched.
Clijsters, who retired in 2012 and now is a mother of three, won the year-ender three times (2002, 2003, 2010).
She said: "There's always something special about the WTA Finals. It's one of the biggest and proudest achievements of my career and I'm really excited to be an ambassador for the WTA Finals. I look forward to see who will make it to the top eight."
Reigning champion Dominika Cibulkova was also at the launch, despite having to pull out from the Stuttgart competition due to a wrist injury.
Re-living the biggest win of her career, she said: "I look at my trophy almost every day and it reminds me of a great moment of what I was able to win. It was full of emotion."
Players on the WTA began earning for one of eight singles slots available for the WTA Finals. Czech Republic's Karolina Pliskova and Dane Caroline Wozniakci currently lead the leaderboard on the Road to Singapore.