Known for the "penetrating richness" of his sound,[1] Harrell performed internationally as a recitalist, chamber musician, and soloist with major orchestras over a career spanning nearly six decades.

[4] In November 1962, when he was 18, his mother died from injuries sustained from a two-vehicle crash[4] while traveling from Denton to Fort Worth with pianist Jean Mainous to perform a recital; she was violinist in residence (faculty) at the University of North Texas College of Music.

[8] Just before his mother died, in April 1962, Harrell had withdrawn from Denton High School in his junior year to advance to the semifinals of the Second International Tchaikovsky Competition in Moscow.

In a review of that concert, Harold C. Schonberg of The New York Times declared that "it would be hard to overpraise the beautiful playing" of Harrell, adding "this young man has everything".

The audience for this historic event, which was the Holy See's first official commemoration of the Holocaust, included Pope John Paul II and the Chief Rabbi of Rome.

[4] Harrell and Nightengale also founded HEARTbeats, which "strives to help children in need harness the power of music to better cope with, and recover from, the extreme challenges of poverty and conflict.

"[19][20][5] Harrell seldom trusted his instruments to airline baggage handlers and in 2012 he achieved a certain amount of notoriety when Delta Air Lines kicked him out of its frequent-flier program for registering and traveling with his cello, which had been enrolled as “Mr.