Levi Watkins Jr., MD, a pioneering cardiac surgeon known for both clinical and civil rights achievements, died April 11 of complications from a stroke. He was 70 years old.

Johns Hopkins University Medical School in Baltimore, where he had started as an intern in 1970, became a professor of cardiac surgery in 1991 and held a vice dean position at the medical school until his retirement in 2013, announced his death.

As a surgeon at Johns Hopkins, Dr. Watkins performed the first implant of an automatic implantable defibrillator in a human heart in 1980. He continued to work on refinements to defibrillators and cardiac resynchronization devices.

He was the first African-American student admitted to Vanderbilt Medical School in Nashville, Tenn., in 1966 and the first to graduate from there four years later. After completing a surgical internship at Johns Hopkins, he became the hospital’s first African-American chief resident in cardiac surgery. He took a two-year break from Johns Hopkins in the mid-1970s to conduct post-doctoral research on renin-angiotensin blockers at Harvard Medical School in Boston.

In 1979, he became a member of Johns Hopkins’ admissions committee, and helped the medical school increase its minority representation by 400 percent within four years. The Robert Wood Johnson Foundation also credited him for the launch of its Minority Medical Faculty Development Program in 1983.

“Levi was known far and wide for his pioneering surgical work, his mentorship to so many young people, his advocacy for minorities and his service as a role model,” Duke Cameron, cardiac surgeon-in-charge at Johns Hopkins Hospital, said in a release. “And he was a powerful spiritual leader to countless others. He probably spoke at as many churches as he did at medical meetings.”

He was born in Parsons, Kansas, and moved with his family to Alabama. He attended the Dexter Avenue Baptist Church, then led by Martin Luther King Jr., and participated in civil rights activities.

At Johns Hopkins, he founded and hosted an annual Martin Luther King Jr. Commemoration event. This year’s celebration included an unveiling of his oil portrait, which was formally installed in the cardiac surgery division in early April.