The 42-year-old Democrat defeated his Republican rival Curtis Bashaw to secure a Senate seat for New Jersey, becoming the first ever Korean-American to serve in the upper house.
The three-term congressman's victory comes after the fallout from a corruption scandal involving former New Jersey Senator Robert Menendez who resigned after being convicted of taking bribes.
"I say to you from the bottom of my heart as the Jersey kid who never thought he would be able to say this: I am your next United States senator," Kim told supporters after his victory. "The greatness of America is not what we take from this country but what we give back."
Kim's victory was widely anticipated as he maintained a steady lead throughout the race.
After studying political science at the University of Chicago, he earned his master's and doctorate in international relations at the University of Oxford.
Kim is expected to be sworn in later this month.
