The video reached more than 17,000 views in less than 24 hours.
Eyewitness News tracked down the "velvet voice," which belonged to Maurice Hill.
"I love singing and I love writing music. That's what I really love to do," Hill said.
Homeless man talks about his "Happy Birthday" rendition
The 50-year-old told Eyewitness News he's been down on his luck most of his adult life after serving time in prison for a crime.
In the 1980s, Hill said he tried to follow his passion for music and joined several bands, but it all fell flat.
"I tried to come out a couple of times, but things and finances weren't right," he said.
Then, Hurricane Harvey hit.
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His low-income apartment was ruined with mold and he wound up under a bridge in downtown Houston.
"Two blankets and my pillow," Hill said, showing the duffle bag he lives out of.
Even with only six possessions to his name, Hill says he refuses not to smile.
"Some people got less than that," he added.
Hill does have a voucher to help get an apartment, but he says he just has not found the right one.
WATCH: Extended video of the sweet serenade
Houston homeless man steals hearts with sweet serenade