He had lived with Alzheimer's disease and dementia for several years, and suffered a series of seizures in recent weeks, his family said.
He was a champion of outdoor culture, and his businesses, the only privately owned operations in the 650,000-acre expanse, attracted everyone from truant school children to Hollywood stars.
Long after selling the ski resort and namesake restaurant in separate deals in 2000 and 2001, respectively, Newcomb remained a frequent visitor, friends said.
"I honestly believe his greatest joy in life was seeing people enjoy and recreate in the forest," said Mike Leum, a longtime member of the Montrose Search and Rescue Team who befriended Newcomb during years of search-and-rescue operations in the Angeles National Forest. "That he had a part in that, I thought always brought him a feeling of accomplishment."
Born May 21, 1920, Lynn Orin Newcomb Jr. was reared in Hollywood. His family's roots were in the San Gabriel Valley, and he spent weekends and holidays there riding and hiking throughout the foothills and in the forest.
There also were occasional visits with a distant cousin, Louie Newcomb, who lived in a remote cabin on a 160-acre parcel that he homesteaded in the San Gabriel Mountains in 1891 just months before the forest was federalized.
That land eventually made its way into the hands of Lynn Newcomb Sr. Inspired by the construction of Angeles Crest Highway, the senior Newcomb founded Newcomb's Ranch Inn, which established itself amid the social constraints of the Prohibition era as a place where one could get a drink or a room without a second glance.
"Word of mouth had it that you could drive up to Newcomb's and get a shot of whiskey or a beer, and it was very unlikely that the sheriffs would drive up there to arrest you," said Dr. Fred Rundall, who has owned Newcomb's Ranch since 2001.
In 1939, Lynn Newcomb Jr., then a student at USC, made his mark when he chose nearby Mt. Waterman as the spot for Southern California's first rope tow. Two years later, a ski lift followed.
"People liked to come because of the proximity," said Newcomb's son, Robyn, who worked at the ski resort while growing up. "You could go up for the day and go skiing and go home."
With the start of World War II, Newcomb dropped out of USC and enlisted in the Army Air Forces, serving as a flight instructor and flying P-38s and P-51s.
After his father's death in 1945, he took on increasing levels of responsibility at Newcomb's Ranch and Mt. Waterman while simultaneously working for Welders Supply Co. in Pasadena and Whittier.
By 1995, Newcomb was scaling back and planning to sell the restaurant and resort.
"People keep coming back here for years," he said in an interview with The Times, reflecting on the previous 50 years. "They all know each other, and they bring their kids back. That's the best part for me."
Newcomb was preceded in death by his first wife, Virginia, and his second wife, Lillian. In addition to his son, Robyn, and daughter, Cynthia Newcomb Quinn, he is survived by six grandchildren and several great-grandchildren.
A memorial service is planned for 1 p.m. Sept. 18 at the La Cañada Flintridge Country Club.