Brooks sold more than 140,000 tickets Saturday morning and his benefit concert for Nashville flood relief ballooned from one show to nine.
"It's great to be a part of the healing," Brooks said in a news release.
The release says the day's sales set a record for tickets sold in Tennessee, besting a concert held by Michael Jackson at Neyland Stadium in Knoxville that drew more than 72,000 fans.
Brooks initially retired about a decade ago to spend more time with his family, but demand for the best-selling solo artist in U.S. history remains high. The 48-year-old musician came out of retirement late last year, announcing a series of shows at the Wynn Resort in Las Vegas that quickly sold out.
The benefit concerts are his only arena shows this year and will include his wife, Trisha Yearwood, his full band and unnamed guests.
He'll now play six shows in nine days from Dec. 16-22 with two shows on Dec. 16, 21 and 22. Tickets were $25 apiece and he raised $3.5 million for The Community Foundation of Middle Tennessee.
May's flood caused more than $2 billion in damage in Nashville alone and 22 people were killed by flooding in middle and west Tennessee.
Nashville's music community was affected with the Grand Ole Opry house closed for five months and thousands of instruments were destroyed when a popular storage and rehearsal space where artists like Brad Paisley and Keith Urban housed their gear was swamped.
There have been a series of benefit telethons and concerts since then hosted by country music stars like Tim McGraw and Faith Hill, and Vince Gill.