Sobuj Khalifa, who arrived in Italy from Bangladesh in 2008, was hailed a hero after saving the 55-year-old Israeli woman on Tuesday, Corriere reported.
The woman lives in Rome and had reportedly attempted suicide.
“I saw the body and at first I thought it was a big fish coming towards me,” he was quoted as saying.
“I then started running along the bank, following the body as it was being dragged by the current. I screamed for help, and all the people watching from the bridge were shouting too.”
He said he then threw himself in “without taking off my shoes or trousers”, managing to pull the woman to safety.
“The woman had a bloated stomach, she had swallowed water. I didn't see her again but I knew she survived.”
“I wasn't afraid,” he added, “I swim well and was a fisherman in my home country.”
Impressed by his act of courage and selflessness, Rome's authorities granted him a one-year residency permit.
Khalifa, who sleeps along the banks of the river, also received a call the next day from Rome mayor Ignazio Marino.
“I called Sobuj Khalifa, the young Bengali who saved a woman from the Tiber,” Marino wrote on his Facebook page.
“I congratulated him on his beautiful heroic and human gesture.”
Despite the honorary permit, Khalifa will return to sleep in a cave under a bridge along the river.
Since arriving in Italy, he has earned a living doing various odd jobs, including selling flowers and umbrellas on the streets of the capital.
He said he now sells flowers in Trastevere, earning €50 a week, which he sends home to his sick mother.
He was initially given a permit to live in the city but that expired a few years ago.