An announcement made Monday said that on May 1, the 53-year-old Vescovo descended 35,853 feet, or almost seven miles into the bottom of Challenger Deep, which is part of the Pacific Ocean's Mariana Trench, according to CNN. Once at the bottom, he explored the seafloor for four hours in his submersible, The Limiting Factor, according to CNN.
The team also found what they think are four new species of amphipods, or shell-less crustaceans.
It is the third time humans have reached the ocean's extreme depths.
His latest dive went 16 metres lower than the previous deepest descent in the trench in 1960.
The group is using a submersible called Limiting Factor to complete its challenge. Robotic landers were also deployed to explore the remote terrain.
"It is nearly indescribable how excited all of us are about achieving what we just did", Mr Vescovo told BBC News.
"Maybe I felt much more like Don Walsh and Jacques Piccard".
A type of long-appendaged amphipod was discovered at the bottom of the Challenger Deep, in the Mariana Trench.
Scientists have found large amounts of microplastic in the guts of deep-dwelling ocean mammals like whales.
"Now in the winter of my life, it was a great honour to be invited on this expedition to a place of my youth".
In the depths, during those five dives, they discovered red and yellow rocky outcrops that could be chemical deposits or bacterial mats, which are made by chemosynthetic microbes, meaning they can convert carbon-containing molecules into organic matter.
Plastic waste has reached epidemic proportions in the world's oceans, with an estimated 100 million tonnes dumped there to date, according to the United Nations.
After spending hours crisscrossing the bottom of the Challenger Deep, collecting video evidence of different wildlife, geological formations and man-made objects, Vescovo stopped for a second.
The Pacific Ocean dive is the fourth in Five Deeps Expedition's plan to dive to the bottom of each of the world's five oceans.
Diving isn't Vescovo's only passion- he's also a climber.
Thus far, in addition to the Mariana Trench feat, Vescovo has become the first human to dive the deepest points in the Puerto Rico Trench of the Atlantic Ocean (27,480 feet in December 2018), the South Sandwich Trench of the Southern Ocean (24,388 feet in January 2019) and the Java Trench in the Indian Ocean (23,596 feet in April 2019). Next, he will attempt to reach the bottom of the Arctic Ocean's Molloy Deep.
In the recent dive, Walsh accompanied a team up above on the ship, as Vescovo descended alone in a submersible called the DSV Limiting Factor.
At its core is a 9cm-thick titanium pressure hull that can fit two people, so dives can be performed solo or as a pair.
As well as working under pressure, the sub has to operate in the pitch black and near freezing temperatures.
Victor Vescovo and his team are in the middle of the Five Deeps Expedition.
Vescovo's journey was filmed for Discovery Channel and has been dubbed the "Five Deeps Expedition".
Victor's team found a plastic bag and sweet wrappers.