The country star won $250,000 (£155,000) for his charity, St. Jude Children's Research Hospital, on Sunday night's finale of the NBC show. He raised a total of $1,291,900 (£800,000) for the organisation.
Academy Award-winning actress Marlee Matlin was named runner-up.
"For The Kids!! Thank you Mr.Trump for the opportunity! 250k on its way to @stjude! I'm blown away.... love ya'll! JR (sic)" Rich wrote on his Twitter account following the win.
In a later press release, he said: "Today has been an unbelievable day! I got Trump to put on a Stetson hat on national television and now I get to drive down to Memphis with a $250,000 check for St. Jude Children's Research Hospital.
"This entire experience has been for the kids and I'm so excited to raise money for this cause and help save lives."
The Big and Rich star also sent his best wishes to Matlin, who had been playing for the Starkey Hearing Foundation, saying: "I want to congratulate Marlee Matlin on her outstanding performance on the show and the monies she raised for her charity."
He added: "It's a great day for all of us."
Matlin, who raised $1,050,000 (£650,000) for her charity on the programme, added on her own Twitter account: "Thank you Twitter. I will keep raising money to give deaf kids the gift of hearing and for @starkeyhearing. Feel the love. I love you all."
The Celebrity Apprentice airs on NBC.
Watch John Rich being named winner of The Celebrity Apprentice below: