This Republican presidential candidate has the sickest Donald Trump burn yet
Trump has been the subject of intense criticism from both parties after declaring several weeks ago that Mexican immigrants are "rapists" and drug-runners.
On Saturday, Graham told Business Insider that Trump was using needlessly divisive, un-presidential rhetoric.
"He's running to be president of all of us," Graham said. "It takes a level of maturity and thoughtfulness and demeanor that's not being exhibited here."
The Senator also made several cracks about recent decisions by businesses like NBC and NASCAR to cut ties with the real estate mogul.
"As a general rule, it would be hard to get elected president if you can't represent a mattress company," Graham said, referencing Serta's announcement that the company would not renew its contract to carry the reality television star's line of mattresses.
Graham did emphasize, however, that he admired Trump's business success and was appreciative of Trump's contributions to Graham's Senate primary campaign.
The Republican primary field is slowly starting to weigh in against Trump. Earlier this week, former New York Gov. George Pataki got into a Twitter feud with the real estate mogul and called on his fellow Republican candidates to denounce Trump.
Graham's comments mirror similar former Florida Gov. Jeb Bush's statements on Saturday. According to the Washington Post, Bush said he was "absolutely" offended by Trump's statements.
"Yeah, of course. Absolutely. And a lot of other people as well," Bush said, according to the Washington Post. "But politically - we're going to win when we're hopeful and optimistic and big and broad rather than ... just [being] angry all the time. This is an exaggerated form of that and there is no tolerance for it."
Though a vocal and influential presence in the Senate, Graham is considered a longshot in the presidential contest. A recent CNN poll found the Senator trailing behind almost every Republican candidate.