Lawmakers passed the $1.4 trillion tax bill early Saturday morning with a 51-49 vote.
Sen. Bob Corker is the only Republican senator to vote against the bill.
Sen. Bob Corker says he will vote against the Senate's current tax reform bill, citing his concerns about it adding to the national debt.
“This is yet another tough vote. I am disappointed. I wanted to get to yes. But at the end of the day, I am not able to cast aside my fiscal concerns and vote for legislation that I believe, based on the information I currently have, could deepen the debt burden on future generations," Corker said in a statement.
“My concern about the impact a rapidly growing $20 trillion national debt will have on our children and grandchildren has been a guiding principle throughout my time in public service. And during my 10 years and 11 months in the Senate, I have consistently fought for fiscal discipline in Washington," he said.
My statement on the tax reform legislation: pic.twitter.com/LdTQRezdlO— Senator Bob Corker (@SenBobCorker) December 1, 2017
Corker is now the only Republican senator to say he will vote against his party's $1.4 trillion tax bill.
His decision won't affect the measure's fate. GOP leaders have already said they have enough votes to push the legislation through the Senate in a vote they hope will come later Friday.
Corker's decision is not a surprise. He had expressed concerns that the measure would add more red ink to the government's $20 trillion in accumulated debt.
Corker has broken openly with President Donald Trump, questioning his stability and warning he might cause World War III.
Corker said he told Trump of his decision, and isn't ruling out backing a compromise House-Senate tax bill.
Shortly after Corker released his statement, Tennessee's senior Senator Lamar Alexander tweeted his support for the Republican tax bill.
"I support the Senate tax reform bill because it is good for Tennesseans’ family incomes in two ways: First, middle-income tax cuts leave more money in the pockets of Tennesseans; Second, taking the handcuffs off job creators will grow the economy, create jobs and raise wages," Alexander said.
I support the Senate tax reform bill because it is good for Tennesseans’ family incomes in two ways: First, middle-income tax cuts leave more money in the pockets of Tennesseans; Second, taking the handcuffs off job creators will grow the economy, create jobs and raise wages.— Sen. Lamar Alexander (@SenAlexander) December 1, 2017
The Associated Press contributed to this story.