Einstein subsequently opened a private practice and co-founded a medical group in Bakersfield, specializing in Internal Medicine.
While maintaining his private practice, he gave weekly lectures and led grand rounds at Los Angeles County+USC Medical Center starting in 1962.
He closed his private practice and left Bakersfield to become Medical Director and CEO of Barlow Respiratory Hospital in Los Angeles, CA.
While living in Los Angeles, he also spent time directing staff and education programs at Los Angeles Good Samaritan Hospital, served as President of the LA chapter of the American Lung Association for one year, and opened an early AIDS treatment center at Barlow Respiratory Hospital.
In 1988, Einstein was offered the position of Medical Director at both Los Angeles Good Samaritan and Bakersfield Memorial Hospitals.
He also treated patients at the Valley Fever Clinic at Kern Medical Center, started the Respiratory Technician program at San Joaquin Valley College, taught at California State University Bakersfield, and established a need- and academic-based scholarship for pre-medical students at CSUB.