The big cat was reported in a heavily wooded backyard of a home bordering the Santa Barbara Golf Club, two blocks north of U.S. Highway 101.
Wildlife officers determined the lion was not in a place where it could be chased it back into the wild without taking action.
A plan was formulated to tranquilize the animal and return it to open space; there were no plans to destroy the animal.
About 12:30 p.m., wildlife officers successfully used a tranquilizer gun to immobilize the cat and secure it for evaluation and transportation.
The cat is a young, male lion, about 100 pounds and appears to be healthy.
Officers took the animal to Los Padres National Forest for release.
A nearby elementary school was notified as a precaution, but was not locked down or evacuated.