The footage, recorded about 11:30 a.m., shows the animal strolling through a patio area and jumping over a gate at the side of the home.
Animal control officers investigated the sighting and determined there was no unusual behavior by the big cat, which seemed to simply be passing through the area.
Newhart Middle School, on Veterans Way, was put under a shelter-in-place order after the sighting.
Mission Viejo Animal Services said additional patrols were being provided in the area of La Paz Road and Arbolitos due to the incident.
"While mountain lions have always roamed the wide green belts and creeks through southern Orange County, with the increase of technology and motion-sensor cameras, sightings have become much more prevalent," the agency said in a statement. "Mountain lions are generally extremely elusive animals and avoid contact with humans."