Swalwell made the announcement during a taping of CBS's "The Late Show with Stephen Colbert," which airs later on Monday. The program tweeted a clip of Swalwell saying he was running for president.
"I'm ready to solve these problems, I'm running for president of the United States," Swalwell said.
"Boy, did it feel good to say that," he added.
Swalwell's announcement has been anticipated for months. The US Representative from California reportedly plans to center his campaign around gun control, according to The Hill.
The 38-year-old Iowa native was elected in 2012 to represent California's 15th Congressional District, according to AP.