Trump, facing the first natural disaster of his administration, was joined by his wife, Melania, as he passed out food and hugged, kissed and played with children at Houston's NRG Center, a 700,000-square-foot (65,000 square meter) facility that is now the city's largest emergency shelter.
Trump, who is making his second trip to the stricken state this week, asked Congress late on Friday for an initial $7.85 billion for hurricane recovery efforts. The request comes as Washington faces tough budget negotiations.
Trump told reporters at the center that his administration was moving fast to provide the financing for aid to the devastated region.
"We are signing a lot of documents to get money," he said.
Trump appeared relaxed as he posed for photographs with volunteers and chatted with those relocated to the shelter alongside Texas Governor Greg Abbott.
"It has been a wonderful thing," Trump said of his meetings with the children as he helped serve food to evacuees amid shouts of "Thank you, sir."
The trip may have political implications for Trump, who was criticized for not meeting with victims and not showing more empathy on his first trip to Texas on Tuesday.
Trump stayed clear of the disaster zone earlier this week, saying he did not want to hamper rescue efforts. Instead, he met with Cabinet members, state and local leaders and first responders in the state capital Austin and Corpus Christi, where Harvey first hit, focusing on the logistics of the government response.
According to the Reuters/Ipsos tracking poll, almost 59 percent of the public disapproves of Trump's performance as president.
(Reporting by Steve Holland in Houston and Yeganeh Torbati and Jim Oliphant in Washington; Writing by Dustin Volz; Editing by David Chance and Bill Trott)