 Parker was born in Boston, Massachusetts in 1823 to parents Isaac and Sarah (Ainsworth) Parker.He graduated from Dartmouth College in 1846, and received his medical degree from Jefferson Medical College in 1848.After graduation, he was appointed lecturer on anatomy and physiology at Bowdoin Medical College at Concord, New Hampshire, and there he undertook also the editorship of the "New Hampshire Medical Journal" which he conducted successfully for nine years.