Irena Ivic, a driver for the Milwaukee County Transit System, was stunned when she saw a young child running barefoot down a highway overpass on the morning of December 22.
The video later shows Ivic stopping her bus, running across the street, picking up the crying child and carrying her to the bus.
Another passenger brought her jacket up to the front of the bus to help the boy warm up.
A passenger can be seen getting up and giving her coat to Ivic for the little boy, who quickly fell asleep in his rescuer's arms.
The MCTS said in a statement that the baby was unharmed.
"I couldn't believe that somebody left the child on the street", Ivic said.
WITI spoke with Hasan Ali Abdul Kasim, the baby's father. When he saw the police gathered near his home, and noticed his daughter was not there, he ran outside.
Milwaukee police told FOX6 News no charges were filed in this case.
On Thursday afternoon, Milwaukee County Executive Chris Abele and MCTS officials honored Ivic.
Irena Ivic-Drobnjak is being praised for her immediate action which may have saved the child's life. "She did the right thing", he said of the five-year veteran with the service.