"It's with happy hearts that all Los Angeles city agencies are able to state that we have found Jesse Hernandez," fire Capt. Erik Scott said near the original scene Monday morning.
Jesse was reported missing about 4:30 p.m. the previous afternoon after he fell about 25 feet into the sewer pipe, prompting a massive response from emergency responders.
WATCH: LAFD announces missing boy found 'alive and talking'
He was discovered "where the 134 westbound freeway goes underneath the 5 Freeway" as L.A. Sanitation officials were opening a maintenance hatch to deploy a camera as part of the search, Scott said.
The boy was given a cellphone to call his family, "who, as you can imagine, are overwhelmed with joy," the Los Angeles Fire Department captain said. Firefighter-paramedics attended to Jesse before he was transported to a hospital for treatment and decontamination. He was later released from the medical center.
The teenager and his family were celebrating Easter at Griffith Park on Sunday when he climbed onto an abandoned maintenance shack. When a plank underneath him broke, he plummeted into toxic water that was flowing at about 15 mph.
The drainage pipe is about 4 feet wide and is part of an enclosed sewage system, which provided search-and-rescue teams with few available access points.
More than 100 firefighters participated in the search, along with park rangers and personnel from the Los Angeles Police Department, Department of Water and Power, and the California Highway Patrol.
Jesse was rescued several hundred feet east of where he fell into the sewer. The location is so remote that authorities closed the westbound 134 Freeway before safely extricating the boy, who was dripping wet.
"The first thing they heard is 'Help,'" said Adel Hagekhalil, the sanitation department's assistant director. "They lowered the hose, he caught onto the hose and was reeled back up. He was sat down on the floor and the first thing he wanted was a cell phone to call his family."