President Obama released a statement saying that he and the first lady, along with the rest of America, are "rooting" for the 90-year-old president and wishing him a full recovery.
"Michelle and I send our best wishes to President Carter for a fast and full recovery," the president said in a statement. "Our thoughts and prayers are with Rosalynn and the entire Carter family as they face this challenge with the same grace and determination that they have shown so many times before.
"Jimmy, you're as resilient as they come, and along with the rest of America, we are rooting for you."
Carter also spoke with Vice President Joe Biden.
Carter also received a flood of well-wishes on social media.
Presidential historian Michael Beschloss tweeted a commemorative photo of Carter fishing, taken 35 years ago to the day, when he was still president.
Sen. David Perdue extended prayers from he and his wife to the president.
Bonnie and I extend our heartfelt prayers to President Jimmy Carter and the Carter family. — David Perdue (@sendavidperdue) August 12, 2015
Following the flood of well-wishes, Carter's grandson and former Georgia state Sen. Jason Carter also took to Twitter to extend the Carter family's appreciation for the support.
Carter revealed in a statement today that a recent liver surgery led to the discovery of cancer that has spread to other parts of his body.
"Recent liver surgery revealed that I have cancer that now is in other parts of my body," the former president, 90, said in a statement today. "I will be rearranging my schedule as necessary so I can undergo treatment by physicians at Emory Healthcare."
Carter said that additional details of his disease, once they are known, will be made public as soon as next week.