With a sharp knife, cut the sweet potato into 1/4" x 1/4" (0.6 cm x 0.6 cm) sticks (see the tip for cutting potatoes into fries in the "technique" section).
Preheat the air fryer to 380°F (193°C). Every air fryer is different so you might not need to preheat the appliance. Take half of the sweet potato sticks and place them in the airfryer basket. "Fry" for about 12 minutes, checking on the sweet potato fries towards the end of "frying". (Depending on your model, you might need to take the fries out of the airfryer sooner or keep them in the air fryer longer). The fries should be crispy with a little bit of browning on the edges.
Store leftover fries covered in the refrigerator up to 4 days. Reheat in a 375°F (190°C) oven/air fryer until hot.