House Oversight Committee Chairman Elijah Cummings, D-Md., previously referred to his community of Baltimore as a "drug-infested" area, using a term that President Trump included in a tweet widely panned as a racist attack on the city.
The video, tweeted by the president on Wednesday, showed Cummings lamenting the city's scourge of drugs while speaking during what appeared to be a congressional hearing.
"This morning, I left my community of Baltimore -- a drug-infested area where a lot of the drugs we are talking about today have already taken the lives of so many children," he said. "The same children that I watched 14 or 15 years ago as they grew up, now walking around like zombies."
Trump originally called Baltimore a "rat and rodent infested mess," apparently conjuring allusions to racism for some media outlets. CNN's Erin Burnett, for example, accused Trump of feeding his base's "basest tendencies" by using those words to describe a majority-African American city.
"Infest has become sort of a trope for Trump," she added before pointing to statements about immigrants and inner cities. "Infest is a loaded word throughout history."
The president's son, Donald Trump Jr., responded to the old footage by asking whether Cummings himself was racist.
"Obviously racist... Right? Those are the rules!" he tweeted alongside the video.
Trump has defended himself by claiming that he was "stating plainly what most people already know." "Elijah Cummings has done a terrible job for the people of his district, and of Baltimore itself. Dems always play the race card when they are unable to win with facts. Shame!" he said over the weekend.
Fox News' Charles Creitz contributed to this report.