The 83-year-old Holtz confirmed his positive COVID-19 test Thursday to a Columbia, S.C., television station.
"I don't have a lot of energy right now," Holtz told ABC Columbia.
Holtz guided Notre Dame to the 1988 national championship in his Hall of Fame coaching career. The legendary college football coach also led Arkansas to a co-national title in 1977.
Holtz, who was elected to the College Football Hall of Fame in 2008, retired from coaching in 2004 after 33 seasons on the sideline. He coached at William & Mary, N.C. State, Arkansas, Minnesota, Notre Dame and South Carolina, finishing with a 249-132-7 combined record.
He posted a 3-10 record as head coach of the NFL's New York Jets in 1976.
Holtz, who previously campaigned for President Donald Trump, is set to receive the Presidential Medal of Freedom from Trump before he leaves office in January.