The former president said he was "pleased" to see entrepreneur Vivek Ramaswamy doing so well.
A political newcomer, Ramaswamy performed very well in a recent poll.
"I am pleased to see that Vivek Ramaswamy is doing so well in the most recent Republican Primary Poll, CBS YouGov," Trump wrote on his social media platform, Truth Social.
RealClearPolitics' more raw average has Ramaswamy in fifth behind DeSantis, Pence, and Haley respectively.
In response to Trump's praise, Ramaswamy senior adviser Tricia McLaughlin told Insider, "We're 10 weeks in and just getting warmed up."