US Vice President Mike Pence has sworn in Jim Bridenstine as the 13th NASA Administrator, the space agency said in a statement.
For his new role at NASA, Bridenstine who was the Republican Representative from Oklahoma, resigned from the House of Representatives on Monday. He is the first politician to be named as the NASA administrator.
"NASA represents the best of the United States of America. We lead, we discover, we pioneer, and we inspire. I look forward to our journey together," Bridenstine said late Monday.
Bridenstine was given the oath of office by Pence at the NASA Headquarters in Washington.
"It is a great privilege for me to be here today, to be able to usher in on behalf of the President of the United States what we believe is a new chapter of renewed American leadership in space with the swearing-in of the newest Administrator of NASA, Jim Bridenstine," said Pence.
"Under Space Policy Directive 1, we will send American astronauts back to the Moon, and after that we will establish the capacity, with international and commercial partners, to send Americans to Mars. And NASA will lead the way."
As part of the swearing-in ceremony, Pence and Bridenstine also spoke live with NASA astronauts Scott Tingle, Drew Feustel and Ricky Arnold, who currently are aboard the International Space Station.
"The appropriations bill that is now law renews focus on human spaceflight activities and expands our commercial and international partnerships. It also continues our pursuit of cutting-edge science and aeronautics breakthroughs," Bridenstine told senior agency leadership at headquarters and NASA's centres via video teleconference.
Bridenstine's lack of professional space experience and technical education prompted criticism from Democrats.
He was confirmed on a party-line 50-49 vote by the US Senate on April 19 to serve as the NASA administrator, more than seven and a half months after the administration nominated him to the position.
A former Navy pilot, Bridenstine majored in economics, psychology and business at Rice University and holds an MBA from Cornell University.
During his Navy career, he accumulated 1,900 hours flying time and 333 carrier landings flying E-2C Hawkeye turboprops and, later, F-18 Hornets before leaving active duty to serve as executive director of the Tulsa Air and Space Museum and Planetarium.
He was elected to represent Oklahoma's first congressional district in 2012, serving on the House Armed Services Committee and the Science, Space, and Technology Committee.