Marshall is a certified registered nurse practitioner (CRNP) who specializes in pulmonary, sleep, and critical care. His special clinical interests include asthma, COPD, sleep apnea, insomnia, narcolepsy, lung cancer, pulmonary nodules, interstitial lung disease, and restless leg syndrome.

Marshall earned a Bachelor of Science in nursing and a Master of Science in nursing from Duquesne University. He is certified by the American Academy of Nurse Practitioners, and the Pennsylvania State Board of Nursing.

He is committed to establishing a trusting relationship with his patients, so they feel comfortable to reach out to him at any time. He sees patients 16 and older.