By David Robert | Published: July 1, 2026 | Last Updated: July 1, 2026 | Source: Haven Health Instagram post
WEST HOLLYWOOD, California — Dr. Jack O’Brien, a board-certified family medicine physician, HIV specialist, clinical researcher, and co-founder of Haven Health, has died at the age of 36. Haven Health announced his passing in an official message to patients, confirming that Dr. O’Brien died on June 27, 2026.
Widely respected throughout Southern California’s LGBTQ+ healthcare community, Dr. O’Brien was recognized not only for his clinical expertise but also for his deeply compassionate approach to patient care. His death has prompted an outpouring of tributes from colleagues, patients, and members of the broader medical community who credit him with transforming countless lives through inclusive, affirming healthcare.
What Happened to Dr. Jack O’Brien?
According to an official statement issued by Haven Health, Dr. Jack O’Brien passed away on June 27, 2026, at the age of 36.
The healthcare practice described the news as a profound loss for its staff, patients, and founders, while asking for patience as it works to ensure continuity of care for individuals under Dr. O’Brien’s supervision.
At the time of publication, no cause of death has been publicly disclosed by Haven Health or Dr. O’Brien’s family.
In keeping with responsible reporting standards, this publication will not speculate on the circumstances surrounding his death. This article will be updated should verified information become publicly available.
Who Was Dr. Jack O’Brien?
Dr. Jack O’Brien built a reputation as one of Southern California’s most respected physicians specializing in family medicine, HIV care, and LGBTQ+ health.
Originally from a small town outside Syracuse, New York, he brought what colleagues often described as East Coast determination to every stage of his medical career.
After earning his Doctor of Osteopathic Medicine degree from the New York Institute of Technology College of Osteopathic Medicine (NYITCOM), Dr. O’Brien completed his residency training at Bayonne Medical Center, where he developed the clinical foundation that would shape his patient-centered philosophy.
He later became a Board-Certified Family Medicine Physician and an American Academy of HIV Medicine (AAHIVM)-certified HIV Specialist, dedicating his career to expanding access to compassionate, evidence-based healthcare for underserved communities.
Patients frequently described him as a physician who made them feel genuinely heard—an attribute that colleagues say defined both his medical practice and his leadership.
A Leader in HIV Medicine and Clinical Research
Beyond caring for patients in the exam room, Dr. O’Brien made significant contributions to HIV research.
Throughout his career, he served as both Primary Investigator and Sub-Investigator on numerous clinical trials involving leading pharmaceutical and biotechnology companies, including:
- GlaxoSmithKline (GSK)
- ViiV Healthcare
- Gilead Sciences
- Merck
His participation in these studies helped advance research into HIV prevention, treatment, and long-term patient outcomes at a time when innovations continue to improve quality of life for people living with HIV.
Colleagues say he believed that clinical research and compassionate patient care should work hand in hand—ensuring today’s patients benefited while helping shape tomorrow’s standards of care.
Building Haven Health
Dr. O’Brien co-founded Haven Health alongside Matty Brownell with the goal of reimagining primary care through a model built on accessibility, trust, and inclusivity.
As the organization’s Chief Medical Officer, he helped create a practice specifically designed to deliver affirming healthcare for LGBTQ+ patients while maintaining comprehensive primary care services for the broader community.
According to Haven Health, the practice itself grew directly from Dr. O’Brien’s vision.
The organization wrote that his approach to medicine became the blueprint upon which Haven Health was built and that his mission extended well beyond individual appointments.
Haven Health Shares Emotional Tribute
In its message to patients, Haven Health reflected on the qualities that made Dr. O’Brien such an extraordinary physician.
“Jack had a gift for making people feel seen. It’s what drew him to medicine in the first place, and it’s what made him such a remarkable physician. He was extremely proud to be a Board-Certified Family Medicine Physician and HIV Specialist devoted to LGBTQ+ health. But if you were his patient, you already know that.”
The statement continued by emphasizing that Haven Health would continue operating according to the principles Dr. O’Brien helped establish.
His co-founders reaffirmed their commitment to carrying forward the work the three founders began together and preserving the compassionate model of care that defined his career.
Continuity of Patient Care
Recognizing the impact Dr. O’Brien’s passing would have on patients, Haven Health also outlined plans to maintain continuity of care.
The practice announced that patients directly under Dr. O’Brien’s supervision would receive follow-up communication regarding medical records, transfer options, and ongoing treatment.
Haven Health expects to resume patient-facing operations on Wednesday, July 8, 2026, with Jake Collins, PA-C, and medical assistant Sharla Blakely supporting clinical services during the transition.
Dr. Jack O’Brien’s Legacy
Although his life was cut tragically short, Dr. Jack O’Brien leaves behind a legacy measured not simply by medical credentials, but by the thousands of patients whose lives he touched.
His career reflected a rare combination of clinical excellence, scientific curiosity, and profound empathy.
Whether conducting HIV clinical research, mentoring colleagues, treating patients, or building Haven Health into an organization centered on dignity and inclusion, Dr. O’Brien consistently placed people before process.
For many patients, he represented the kind of physician who combined expertise with humanity—a doctor whose greatest strength was making every individual feel respected and understood.
His influence will continue through the practice he helped build, the colleagues he mentored, and the communities he served.
Funeral and Memorial Information
As of July 1, 2026, Haven Health has not announced the date or location for Dr. Jack O’Brien’s Celebration of Life.
The organization said memorial details will be shared once arrangements have been finalized and invited members of the community to assist in identifying an appropriate venue capable of accommodating the many people whose lives Dr. O’Brien impacted.
Memorial Details
Location: To be announced
Date: To be announced
Time: To be announced
Public Attendance: Additional information will be released by Haven Health when available.
Frequently Asked Questions
How did Dr. Jack O’Brien die?
Haven Health confirmed that Dr. Jack O’Brien died on June 27, 2026. As of publication, no cause of death has been publicly disclosed by the organization or his family.
How old was Dr. Jack O’Brien?
Dr. Jack O’Brien was 36 years old.
What was Dr. Jack O’Brien known for?
He was a Board-Certified Family Medicine physician, AAHIVM-certified HIV specialist, clinical researcher, and co-founder of Haven Health. He was especially recognized for his dedication to LGBTQ+ healthcare and HIV medicine.
Where did Dr. Jack O’Brien receive his medical training?
He earned his Doctor of Osteopathic Medicine degree from the New York Institute of Technology College of Osteopathic Medicine and completed his residency at Bayonne Medical Center.
Will Haven Health continue operating?
Yes. Haven Health has confirmed that the practice will continue under its existing leadership, with patient services expected to resume on July 8, 2026.
Editorial Standards
This obituary has been prepared using official statements released by Haven Health, verified professional biography information, and publicly available records concerning Dr. Jack O’Brien’s medical training and career. No unverified claims or speculation regarding the circumstances of his death have been included. Information about funeral arrangements and any additional announcements will be incorporated as they are confirmed by the family or Haven Health.