Our Faculty

Our faculty strives to live up to their reputation of being the most supportive and approachable, while teaching residents to treat a diverse, under-served patient population. We focus on training outstanding, balanced residents, in a hospital and outpatient environment dedicated to teamwork, community service, work/life balance and physician wellness.

For information on our faculty, email us:  [email protected]     


Dr. Gregory Lewis

Gregory R. Lewis, MD, FAAFP | Program Director

Gregory Lewis specializes in the primary and hospital care of all patients.  This includes newborns, children, teenagers, adults, geriatrics, and obstetrics/gynecology patients.  He received his medical degree from the University of Wisconsin – Madison and completed his post-graduate training at St. Luke’s Family Practice Residency Program in Milwaukee. He spent the first half of his career in various positions in Arizona and moved to Southern California in July, 2016.  Devoting his life to academic medicine, he gets great pleasure out of watching his residents progress professionally into compassionate, outstanding young physicians.  In his spare time, he enjoys doing yard work, cooking and keeping active with aerobic exercise.


Dr. Armaity Austin

Amaity V. Austin, MD, MPH, FAAFP, ABoIM 

Armaity V. Austin is dually board certified physician in Family Medicine and Integrative Medicine. She is committed to working with and serving underserved patients in the community. Dr. Austin has over twenty years of teaching experience, having taught medical students at University of Arizona College of Medicine and Keck School of Medicine of USC. She also teaches Family Medicine residents in Phoenix and Los Angeles. Currently, Dr. Austin leads the community medicine curriculum at our residency. She is Faculty Director of the Integrative Medicine Residency Track at CHMC Family Medicine Residency. She is the Department Chair of Family Medicine at CHMC. Her interests include Community Medicine, Bioethics, Global Health, and Integrative Medicine. She enjoys traveling, photography, ethnic cuisine, music and yoga.     


Dr. Hector Castillo

Hector Castillo, MD

Hector Castillo has been in practice for 16 years is currently a primary care physician and a hospitalist. He completed his undergraduate degree from Occidental College majoring in Biology. He graduated from the University of Southern California, Keck School of Medicine and completed his internship and residency at White Memorial Medical Center. Dr. Castillo serves on multiple clinical leadership committees at White Memorial Medical Center and at AltaMed Health Services. He is a proud husband and father of three wonderful children. He coaches flag football and enjoys time with his family.     


Dr. Michelle Crespo

Michelle Crespo, MD, MPH 

Michelle Crespo currently serves as core faculty for the California Hospital Medical Center Family Medicine Residency Program, where she completed her residency. She obtained her medical degree from University of California Irvine School of Medicine where she participated in the Program in Medical Education for the Latino Community (PRIME-LC) program. She has a master degree in public health from University of California Los Angeles Fielding School of Public Health, focusing on health policy and management. Her interests include full-spectrum family medicine, addressing healthcare disparities, and advocating for increased health access. For fun, she likes to watch NBA games, attempt CrossFit workouts, and take trips to Disneyland.      

Dr. Richard Hernandez    

Richard Hernandez, MD

Richard Hernandez works as a core faculty member at the California Hospital Family Medicine Residency program. He received his medical degree from Ross University School of Medicine and completed his residency at Arrowhead Regional Medical Center in Colton, CA. His interests include working in the inpatient as well as urgent care setting. On his spare time, Dr. Hernandez is an avid weightlifter and cook and enjoys spending time with his wife and 2 daughters at Disneyland.     

Dr. Mark McDowell    

Mark McDowell, MD 

Mark McDowell is a Family Physician originally from Ohio now making Los Angeles his home.  He completed residency training in New York City at Beth Israel.  He has been affiliated with the Dignity program for 4 years, and helps direct the clinic procedural curriculum. His interests in medicine include reproductive health, pediatrics and community medicine.    

Dr. Juan Silva

Juan A. Silva, MD

Juan A. Silva graduated from University of California, Riverside after attending Abraham Lincoln High School in Los Angeles. He graduated from University of California, Davis School of Medicine. Dr. Silva completed his internship and residency at White Memorial Medical Center in Family Medicine. He is currently a Family Physician and Founder of Mosaic Family Care, and a core Faculty of the California Hospital Medical Center Family Medicine Program. Dr. Silva serves on multiple leadership committees at White Memorial Medical Center, East Los Angeles College Foundation, and Monterey Park Hospital. He is a proud husband and father of 7 children. He enjoys sporting events, and above all spending time with family and friends.     

Dr. Anthony Zamudio

    Anthony Zamudio, PhD 

Anthony Zamudio is the Director of Behavioral Science at the California Hospital Family Medicine Residency program with over twenty-years teaching residents, medical students, and psychology graduate students the psychosocial, cultural and ethical aspects of primary care.   He has multiple journal publications on patient encounters in primary care. He’s a member for the LACPA Ethics Committee and a former ethics member of the California Psychological Association.