Attorney John Rock was the first African American to be admitted to the Bar of the Supreme Court of the United States. In addition to being an accomplished attorney, he was also a teacher, doctor and abolitionist. Rock’s initial professional life was in the medical field. He first entered the field of dentistry as he was precluded from medical school initially based upon this race. After an apprenticeship and opening his dental practice in Philadelphia in 1850, he was admitted into medical school in Philadelphia in 1852. He was one of the first African Americans who obtained a degree in medicine. At the age of twenty-seven, he had already established himself as a talented and well-respected dentist and physician. Rock is credited with treating many patients on the way through Boston on the Underground Railroad to Canada.

As a result of health-related problems, Rock left his medical practice and began to study law in 1860 and shortly thereafter gained admittance to the Massachusetts Bar. He opened a private law practice where he advocated diligently for the rights of the African Americans. On February 1, 1865, Republican Senator Charles Sumner nominated Rock as the first black American to become a member of the United States Supreme Court Bar. Rock was then introduced before the United States House of Representative, becoming the first African American attorney to be introduced to Congress.