Hemsley dropped out of school after the tenth grade and joined the United States Air Force, where he served for four years.

On leaving the Air Force, Hemsley returned to Philadelphia, where he worked for the United States Postal Service during the day while attending the Academy of Dramatic Arts at night.

[2][3] Hemsley performed with local groups in Philadelphia before moving to New York to study with Lloyd Richards at the Negro Ensemble Company.

Shortly after, he joined Vinnette Carroll's Urban Arts Company appearing in these productions: But Never Jam Today, The Lottery, Old Judge Mose is Dead, Moon on a Rainbow Shawl, Step Lively Boys, Croesus, and The Witch.

While Hemsley was on Broadway with Purlie, Norman Lear called him in 1971 to play the recurring role of George Jefferson in his new sitcom, All in the Family.

Hemsley then was a voice actor in the ABC live-action puppet series Dinosaurs, where he played Bradley P. Richfield, the boss of the main character, Earl.

In 2001, Hemsley appeared as a contestant on the "Celebrity Classic TV Edition" special of ABC's hit primetime quiz show Who Wants to Be a Millionaire and won $125,000 for his charity.

In 2011, he reprised his role as George Jefferson for the final time, alongside Marla Gibbs as Florence Johnston, on Tyler Perry's House of Payne.

"[14] Hemsley died at his home in El Paso, Texas on July 24, 2012, at age 74 due to superior vena cava syndrome, a complication associated with lung and bronchial carcinomas.

He had a malignant mass in one of his lungs for which chemotherapy and radiation had been recommended, according to the El Paso County Texas Medical Examiner's report.

[15][16][17] On August 28, 2012, an El Paso news anchor interviewed Flora Isela Enchinton, the sole beneficiary of Hemsley's will, who said that the two were friends and had been business partners for more than two decades.

[20] On November 9, 2012, the legal battle over Hemsley's body ended when Judge Patricia Chew ruled in favor of Enchinton.