William Hasley, the writer and longtime friend of Caitlyn Jenner, has died after collapsing while hiking in Los Angeles’ Runyon Canyon on Saturday evening.
Emergency responders rushed to the scene, but despite resuscitation efforts, the 78-year-old was pronounced dead shortly after being found.
Authorities confirmed that Hasley was located off Nichols Canyon Road near Hollywood Boulevard at around 6:42 p.m., after hikers alerted emergency services.
The cause of death has not yet been determined.
Emergency Rescue Efforts Failed to Save Veteran Writer
According to the Los Angeles Fire Department, air operations teams were deployed quickly after reports of a medical emergency on the trail.
Rescuers were lowered to the location where Hasley had collapsed, and emergency treatment was administered on-site.
Despite rapid intervention, officials confirmed that the writer did not survive.
Investigators have not yet disclosed whether environmental conditions, health complications, or other factors contributed to his sudden death.
The incident has added to concerns about the risks associated with the popular but steep hiking routes in the Hollywood Hills area.
Hollywood Career Spanning Screenwriting and Publishing
Hasley was widely known in entertainment and literary circles, having worked as a screenwriter with major studios including Universal Pictures, Warner Bros., and 20th Century Fox.
His career spanned decades in Hollywood, where he contributed to various film and television projects.
In addition to his screenwriting work, he co-authored Caitlyn Jenner’s 1996 self-help book Finding the Champion Within, published by Simon & Schuster.
The book focused on motivation, discipline, and personal development, and became part of Jenner’s early post-Olympic public identity.
Personal Life and Connection to Caitlyn Jenner
Beyond his professional accomplishments, Hasley was known for his close association with Caitlyn Jenner and her extended circle.
He maintained a long-standing friendship with the Olympic gold medalist and was considered part of her wider professional network for many years.
Hasley was also briefly married to actress Robin Riker in 1987, a detail often referenced in profiles of his personal life.
Representatives for Jenner have not yet publicly commented on his passing.
Tragedy Comes Amid Difficult Period for Jenner
Hasley’s death marks the second major loss connected to Caitlyn Jenner’s inner circle in less than a year.
In July 2025, Jenner’s close friend and former manager Sophia Hutchins died in a fatal accident near Jenner’s Malibu residence.
Hutchins, who had been part of Jenner’s professional and personal life for years, was killed after an ATV incident that sent her vehicle off a steep cliff.
She had previously appeared on Jenner’s reality series and worked closely with her following Jenner’s transition and public coming-out in 2015.
Despite speculation in the past, Hutchins consistently maintained that their relationship was strictly professional and based on friendship.
Investigation Into Runyon Canyon Death Ongoing
As authorities continue to investigate Hasley’s death, no official conclusion has been reached regarding what caused him to collapse on the hiking trail.
The Los Angeles County medical examiner is expected to release further findings after completing an autopsy.
Runyon Canyon, a well-known hiking destination overlooking Hollywood, attracts thousands of visitors daily but has also seen multiple emergency incidents due to its steep terrain and high temperatures.
Hasley’s passing has prompted tributes from colleagues and acquaintances across the entertainment industry, who remember him as a seasoned writer and respected creative voice in Hollywood.
