Ronald Isley, lead singer of the Isley Brothers, is facing a maximum 26-year jail sentence after being convicted in the US of multiple tax evasion charges.
Ronald Isley (left) suffered a minor stroke last year
Isley, whose band's hits included This Old Heart of Mine and Summer Breeze, denied five counts of tax evasion and one of failing to file a tax return.
Prosecutors said he had demanded cash for live shows and used other members' royalty cheques for himself.
Sentencing will be determined in January next year, the court said.
A federal jury in Los Angeles convicted Isley, 64, of all five counts of tax evasion and one count of wilful failure to file a tax return.
The court heard how the soul singer, a co-founder of the Isley Brothers, evaded the US tax service by demanding case payments for millions of dollars in performance fees he earned between 1997 and 2002.
He also put homes and a yacht in the names of his then-wife or corporations, and cashed royalty checks belonging to his late brother and former band member O'Kelly Isley, according to the government.
Isley's latest albums, released last year, were a collaboration with Burt Bacharach, called Here I Am, and the Grammy-nominated Isley Brothers CD, Body Kiss.