At his first campaign event in Waterloo, Iowa, Sestak told an audience of four caucus-goers that "Americans want someone they can trust."
"Americans want someone who is accountable to them above self, above party, and above any special interest," Sestak said. "They want a President that has a depth of global experience to restore U.S. leadership to the world and to protect our American dream at home."
Sestak, who served in the Navy for more than 31 years, joins a historically crowded field of Democrats looking to take on President Trump in 2020. In a recent CBS News/YouGov poll of registered Democrats in early primary states, 71% said there are too many choices.
In his announcement video, Sestak explained he joined the race later than other candidates because his daughter was battling brain cancer. "The decision to delay was so I would be there with Alex, our daughter, as the brain cancer she courageously beaten at four years old returned this past year." He noted that his daughter "has again overcome the single-digit odds."
The retired admiral told reporters in Waterloo he plans to get his message out in the field of 24 other candidates "step by step." He added that voters "want to know if I know them, not if you just know me and the policies."
Sestak defeated 10-term Pennsylvania Republican Wayne Curtis Weldon in 2007 for a House seat and won reelection in 2009 in a traditionally red district. He said his daughter's initial battle against cancer inspired him to serve in the House "in order to work for all Americans to have health care coverage we fortunately had for Alex."
Sestak said he will work on having a public option for health care right away, but added millions of Americans have some form of private health care and cautioned against immediately eliminating private health insurance. He said he wants to see "a transition of choice," so that voters who prefer private insurance don't have to "change their health care plan in two to four years."
The former congressman touted his record as a Democrat in Pennsylvania's traditionally red 7th District while pushing for progressive policies like universal background checks for gun owners and supporting a woman's choice to reproductive health care.
While speaking to potential caucus-goers, Sestak highlighted his experience in national security and said that "an illiberal world order is beginning to emerge." He described the Trump administration's actions internationally as bordering isolationism and warned that America's "retreat from the world will lead to the contraction of the American dream."