The outing came as Trump courts Senate support for his tax and immigration plans. He's currently feuding with GOP Sen. Bob Corker of Tennessee, and with only 52 Republican-controlled Senate seats, Trump can ill afford to lose significant support among his party to pass his legislative agenda.
After the round, Graham tweeted his praise for Trump's golf game and offered some self-denigrating humor about his own golf skills and failed presidential bid.
"Really enjoyed a round of golf with President @realDonaldTrump today. President Trump shot a 73 in windy and wet conditions!" Graham tweeted. "How bad did he beat me? I did better in the presidential race than today on the golf course! Great fun. Great host."
White House deputy press secretary Lindsay Walters told reporters after Monday's golf meeting that Trump and Graham discussed immigration, tax reform, government funding and health care.
The lighthearted comments from Graham, a South Carolina Republican and frequent critic of the President who unsuccessfully ran against him in the 2016 presidential primaries, contrasted sharply with some of the more contentious moments that have defined the long and complicated relationship between the two.
During the election, Trump famously read Graham's personal cell phone number out loud to hundreds assembled for a South Carolina campaign rally in July 2015. Even after Graham dropped out of the election, he continued to slam Trump's campaign, telling voters they should tell Trump he should "go to hell."
"He's a race-baiting, xenophobic, religious bigot," Graham told CNN in 2015
However, the two appeared to bury the hatchet and swap digits in March when Graham visited the White House to meet with Trump.
"How good was the meeting with @POTUS?" Graham tweeted after the lunch
. "I gave him my NEW cell phone number."
But things took a turn again when Trump and Graham clashed in August after the President's response to racially motivated protests in Charlottesville, Virginia. Graham accused Trump of stoking tensions
, a claim Trump called "a disgusting lie."
Third visit to Trump's golf club this weekend
Trump's golf trip makes it the third day in a row that the President -- who has no public events listed on his schedule Monday, which is Columbus Day -- visits his own property this holiday weekend.
Trump has now spent 72 days as President at one of his own golf properties, according to CNN's count.
In total, Trump has spent 80 days at a property bearing his name -- about 30% of the days he has been President.
This does not count his visits to Mar-a-Lago -- 25 days over seven weekends -- but there is some crossover given his frequent golf visits in South Florida.
Trump has now spent 30 weekends as President at one of his properties.
For months, Democratic legislators have written letters to the White House and federal agencies in an attempt to hold the administration accountable for what they say are violations of ethical traditions and norms.
But the Democrats have little to show for their efforts so far, in part because their Republican counterparts haven't added their voices to the Democrats' requests.