Incumbent U.S. Sen. Brian Schatz won his Democratic primary race Saturday, defeating four challengers in his bid for his first full term in office.

Schatz easily advanced to meet Republican John Carroll in the November general election.

Schatz had an unlikely road to the Senate. When Hawaii's beloved Sen. Daniel Inouye died in December 2012, it was left to then-Gov. Neil Abercrombie to fill the seat. Inouye's dying wish was to have then-U.S. Rep. Colleen Hanabusa fill the seat, but Abercrombie instead chose Schatz, his lieutenant governor.

Two years later, Hanabusa challenged Schatz but lost in a special election to fill the last two years of Inouye's unexpired term.

Other Democratic candidates in Saturday's race included Makani Christensen, Tutz Honeychurch, Artuto Reyes and Miles Shiratori. The Republican candidates included Carroll, Karla Gottschalk, Eddie Pirkowski and John Roco.

Joao Santos, 53, a Democrat who has lived in Honolulu for 23 years, voted at Kawananakoa Middle School on Saturday and said he has known Schatz for a number of years and feels his re-election is certain. Santos sees infrastructure and homelessness as major local issues that need to be addressed.

"They are critical issues for our economy," said Santos, an insurance agent. "Our number one industry, tourism, homelessness is having a big effect on that."

Maile Chow, 39, a Democrat who also lives in Honolulu and voted at Kawananakoa Middle School, said that she, too, likes Schatz for the Senate.

"I like his young, youthful approach to things and want to see what he can continue to do in the future," she said.

Schatz serves on the Appropriations; Commerce, Science and Transportation; and Indian Affairs committees. He also serves on the Select Committee on Ethics.

He has introduced legislation on reducing the effects of climate change and promoting clean energy. Hawaii leads the nation in its initiatives to become completely energy independent by 2045.

Schatz, who was raised in Hawaii, was a member of the state House from 1998 to 2006. He is married and has two children.