The ad features Donna Stearns Arthur, Acton's mother, criticising Acton for "lying about her opponent" and "her past," including claims that she "grew up living in a tent."
Ramaswamy has come under fire for the ad blitz, and some Republicans, including Ohio Governor Mike DeWine, have called on him to withdraw it from television and digital video platforms.
Trump's comments on Thursday back the candidate against that criticism. The exchange highlights a divide within the Ohio GOP over the use of personal family attacks in the governor's race.