Speaking at a rally in New Hampshire, the Republican frontrunner said Mr DeSantis had done a "very good job". Mr DeSantis's withdrawal leaves just one rival to Mr Trump Nikki Haley.
Donald Trump has described one-time Republican rival Ron DeSantis as a "really terrific person" after the Florida governor ended his presidential campaign and endorsed the former president.
It was a far cry from previous comments from Mr Trump who has previously labelled him as "DeSantimonious" or "DeSanctus".
Ending what was perhaps the most bitter rivalry of the Republicans' 2024 campaign, Mr Trump said: "I just want to thank Ron and congratulate him on doing a very good job.
Speaking at a rally in New Hampshire, he added: "He was very gracious, and he endorsed me. I appreciate that, and I also look forward to working with Ron."
Mr Trump described Mr DeSantis as "a really terrific person".
Earlier in the day, Mr DeSantis said via video that he would be ending his campaign two days before New Hampshire's first-in-the-nation Republican primary.
"It's clear to me that a majority of Republican primary voters want to give Donald Trump another chance," Mr DeSantis said.
"I signed a pledge to support the Republican nominee, and I will honour that pledge."
Meanwhile, the remaining rival to Mr Trump, Nikki Haley, has long prioritised New Hampshire as a potential springboard ahead of her home-state South Carolina primary next month.
However, it is believed Mr DeSantis's supporters are more likely to support the former president.
During Sunday's speech, Mr Trump accused Ms Haley of forming an "unholy alliance" with liberals, never-Trumpers and RINOs, or Republicans in Name Only.
He holds a double-digit lead over his rival in New Hampshire, according to polls, and his campaign hopes a second consecutive win will make his eventual nomination all but inevitable.