It was not immediately clear if the deceased man died from police gunfire or a self-inflicted wound, the LAPD said. No officers were injured.
The standoff took place at a two-story, multimillion-dollar home in the 1600 block of Alta Mura Road. At least 50 rounds of tear gas were also fired into the residence.
Police Lt. Chris Ramirez said that amount of tear gas was fired "to make sure that the house is completely saturated before we make any type of entry."
The incident began shortly after midnight as an altercation between a couple who have been involved in an intermittent relationship with each other, police said. The woman called authorities and said her boyfriend had tried to shoot her.
The woman was safe after she ran out of the 9,000-square-foot home, the LAPD said. The suspect, whom investigators believe had been drinking heavily, remained barricaded inside.
Police were initially in contact with the man, but he stopped communicating with them shortly before 6 a.m., authorities said.
"Time's on our side," Ramirez said, "and when time's on our side we want to use the best tactics that we can -- for the safety of the officers, and the public, and the suspect as well."
At least three LAPD armored vehicles, a crane and a remote-controlled robot were seen on the lush hilltop property as the standoff continued for more than 10 hours.
"Because it's such a large property, that would be why there are so many rounds (fired), for it to be effective," said LAPD spokesman Josh Rubenstein. "In a big property, you can find a lot of different spots to kind of get away from that."
Shortly before 11 a.m., police announced that the suspect was discovered dead from a gunshot wound in a second-floor room in the home. He was not immediately identified.