He had been making his way down the south ridge of 3,000ft-high Tryfan when he slipped on Saturday afternoon.
An RAF Sea King helicopter, based at Valley in Anglesey, was called at 15:00 BST to help him back down the mountain.
The man, in his early 50s, was flown to the Ogwen Valley mountain rescue team base after it was determined he did not need hospital treatment.
A man has been airlifted from a mountain in Snowdonia after injuring his leg while out walking.