Speaking about her new position in a statement, Santiago said Ouya has achieved what other console makers still have not.
"This is the first console company that really understands how important it is to remove the barriers to development," she said.
Santiago co-founded Thatgamecompany six years ago with creative director Jenova Chen, whom she worked with at the University of Southern California on the experimental game Cloud. She left the company last March.
In addition, Ouya CEO Julie Uhrman announced today that Ouya units will ship to backers beginning March 28. The small-sized console's full launch is set for June, where systems will be available through major retail partners like Amazon, Best Buy, Target, and GameStop.
Uhrman also revealed that Portal designer Kim Swift and her Airtight Games studio are developing a new game to be released exclusively on Ouya. An official announcement of that game is expected soon.
What's more, Papo & Yo developer Minority Media is bringing a new adventure game to the console, and Killing Floor developer Tripwire Interactive will release the first-person shooter The Ball and a new title through Ouya.
The Ouya is priced at $99.99, with the touch-screen controllers going for $49.99. A new version of the system is expected to launch every year in an effort to take advantage of falling component prices.