Seijo Oi, MD

Dr. Seijo Oi, a beloved physician and devoted family man, was born on February 5, 1952, in Tokyo, Japan, and passed away on January 12, 2026, in Los Alamitos, California. With a profound impact on the lives of countless individuals during his devoted 45-year career in internal medicine and pulmonary diseases, Dr. Oi dedicated his life to the health and well-being of communities in Hawthorne, CA; Newport Beach, CA; and Kerrville, TX.

A proud 1975 graduate of the University of Washington with a Bachelor of Science in Zoology, Dr. Oi went on to earn his Doctor of Medicine (M.D.) from the University of Washington School of Medicine in 1979, where he was recognized for his academic excellence and commitment by being inducted into Alpha Omega Alpha (AOA). Following his early training, he completed his residency in internal medicine in 1982 and a fellowship in pulmonology in 1986 at Harbor UCLA Medical Center.

Dr. Oi was known for his extraordinary work ethic, quiet wisdom, and deep integrity, qualities that resonated with his colleagues and patients alike. His greatest strength as a physician was his ability to listen—not just to the symptoms presented, but to the fears and concerns behind them. He had an innate ability to make those around him feel understood and cared for, embodying the true essence of compassionate medicine.

Beyond his impeccable medical career, Seijo ensured the safety, support, and success of his wife, Theresa  (Terri), and their four children: Dale, Allison, Kyle, and Madeline. He took immense pride in each of his children’s many personal and professional achievements.

In 2003, Seijo embraced the Catholic faith with deep gratitude, entering the Church through baptism and confirmation on December 13, 2003, at St. Mary's by the Sea in Huntington Beach, guided and welcomed by Father Johnson, whom he always remembered with profound appreciation.

As a much loved grandfather to eight cherished grandchildren, Seijo's happiest moments were spent in their company. In his later years, he found joy in watching them grow. In his free time he had a passion for collecting musical instruments—especially ukuleles—and playing Hawaiian music.

Dr. Seijo Oi is survived by his wife, Dr. Theresa Escalante; his children, Mr. Dale Oi, Mrs. Allison Bellumori; Dr. Kyle Oi, and Mrs. Madeline Dodini; and his siblings, Mr. Shinjo Oi and Dr. Cheiko Lin. The legacy he leaves behind will continue to inspire his family and all who had the privilege of knowing him.

A Rosary/Viewing service will be held in his honor on January 19, 2026, at 5:00 PM, at Forest Lawn - Cypress - Hope Chapel, with a Catholic Funeral Mass service taking place on January 20, 2026, at 9:00 AM, at St Peter Chanel Catholic Church in Hawaiian Gardens.

Dr. Seijo Oi will be deeply missed but forever remembered for the impact he made on the lives of others.