Glen Campbell, the sweet-voiced, guitar-picking son of a sharecropper who became a recording, television and movie star in the 1960s and ’70s, waged a publicized battle with alcohol and drugs and gave his last performances while in the early stages of Alzheimer’s disease, died on Tuesday in Nashville. He was 81.

Tim Plumley, his publicist, said the cause was Alzheimer’s.

Mr. Campbell revealed that he had the disease in June 2011, saying it had been diagnosed six months earlier. He also announced that he was going ahead with a farewell tour later that year in support of his new album, “Ghost on the Canvas.” He and his wife, Kimberly Campbell, told People magazine that they wanted his fans to be aware of his condition if he appeared disoriented onstage.

What was envisioned as a five-week tour turned into 151 shows over 15 months. Mr. Campbell’s last performance was in Napa, Calif., on Nov. 30, 2012, and by the spring of 2014 he had moved into a long-term care and treatment center near Nashville.

Mr. Campbell released his final studio album, “Adiós,” in June. The album, which included guest appearances by Willie Nelson, Vince Gill and three of Mr. Campbell’s children, was recorded after his farewell tour.