Cook and stir sausage in a skillet over medium-high heat until browned, about 8 minutes. Drain.
Mix sausage, onion, cream cheese, and jalapeno peppers together in a bowl until well combined. Spoon about 1 tablespoon sausage mixture onto each crescent dough triangle; fold corners around sausage and roll up into a crescent, ending at the tip of the triangle. Place rolls on baking sheets.
Bake in preheated oven until rolls are golden brown, about 15 minutes.
