Kyndall Jack, 18, was hoisted out of Cleveland National Forest by a rescue helicopter and rushed to a hospital.
"We have confirmed that we have Kyndall, she's been rescued and she is alive," Orange County sheriff's Lt. Jason Park said.
Park said Jack was responsive but dehydrated and weak. There was no information on whether she had other injuries.
CBS Los Angeles reports Jack's family has been notified.
"They cried. They hugged us. They thanked us immensely," Capt. John Muir of the Orange County Fire Authority said.
A reserve deputy suffered a head injury and was also flown to a hospital. Orange County Fire Authority Capt. Jon Muir said the deputy fell 60 feet, but he did not know how it happened.
Park said screams had been heard and ground teams were dispatched along with a helicopter.
"We started to close in. We heard the voice from all our ground crews and surrounded it and made contact with her." he said. "It was very difficult to extract her."
Crews had ramped up efforts to find Jack after her companion was discovered dehydrated and disoriented the night before.
Cendoya and Jack had been missing since 8:30 p.m. Easter Sunday when they called Orange County Sheriff's deputies for help finding their way back to their car.
Their cell phones lost power before authorities were able to pinpoint an accurate GPS location.
After losing contact, deputies began looking on the ground, in the air and on horseback for the hikers in the area below Saddleback Peak and in Trabuco Canyon.
Authorities resumed their search for Jack at daybreak Thursday using dogs and 100 trained searchers lowered into the rugged terrain by helicopter.
Cendoya and Jack, both of Costa Mesa, are students at Cal State Fullerton.
The two were believed to have gone off trail near Holy Jim Trail, a tree-lined dirt path along a creek that leads to a waterfall and is popular with day hikers.
In the 911 call, they said they were about a mile from Jack's car, which was parked at a trailhead, but rescuers expanded the search when they weren't found nearby. When Cendoya was found, he was about a half-mile from the car, authorities said.
Jack's mother drew a message on the car's dusty windshield that read: "Kyndall -- we r looking wont stop love you mom," and signed it with a heart.
"When you're disoriented because you're out of breath and tired and you think you're one mile away, you could be potentially three or four miles away," Muir said Wednesday afternoon. "There's a lot of ground to cover."
The area is in a section of the national forest in the Santa Ana Mountains, which lie along the border of Orange and Riverside counties southeast of Los Angeles. The trail ranges in elevation from about 2,000 feet to about 4,000 feet.