Johnny Crawford, who found early fame in the 1950s as an original Mouseketeer on The Mickey Mouse Club and even more success as the son of Chuck Connors’ title character in the 1958-63 Western series The Rifleman, died Thursday two years after an Alzheimer’s disease diagnosis and a recent battle with Covid-19. He was 75.

Johnny Crawford, best known for his role as Mark McCain, the son of Chuck Connors' Civil War vet character on the late '50s, early '60s TV show, "The Rifleman," died on April 29, 2021. He was 75 years old at the time of his death, according to Variety. He was diagnosed with Alzheimer's in 2019, and later struggled with COVID-19 and pneumonia.