The IOC says the Canadian star was chosen as the fifth and final "ambassador" for the Games, which will take place Jan. 13-22 in Innsbruck, Austria.
The others are figure skater Kim Yu-na, Alpine skiers Lindsey Vonn and Benjamin Raich and freestyle skier Kevin Rolland.
Crosby scored the winning goal for Canada in overtime of the gold-medal game against the United States at the 2010 Vancouver Olympics.
"I have always tried to lead by example and be a positive role model for people," Crosby said.
The Youth Games will include more than 1,000 athletes between the ages of 15 and 18 competing in seven sports.