The top Democrat on the House Oversight and Government Reform Committee said he expects there will be more departures from the Secret Service as an investigation into the agency begins.
The director, Julia Pierson, resigned Wednesday after a series of high-profile security lapses affecting both the White House and President Obama came to light.
"It did not begin with her and it's not going to end with her leaving," Cummings said on CBS' "Face the Nation" Sunday. "There's still people that probably need to go."
"I think there's culture that has developed, the culture of complacency - we see it with these security breaches," he added.
Cummings, who was one of the members that grilled Pierson at a Capitol Hill hearing last week, said the information he has received from whistleblowers suggests the problem "goes back a ways."
"You had agents that were basically afraid, that the information that they wanted to impart to the top person would never get there. They were fearful that there would be retaliation," he said, adding that he "never thought that the Secret Service would have those kinds of issues."
Deputy Secretary of Homeland Security Alejandro Mayorkas and the agency's general counsel will take over the internal review that is being conducted following an incident in which a man jumped the fence at the White House, entered the unlocked doors and ran all the way to the East Room before being apprehended.
Department of Homeland Security Secretary Jeh Johnson said he plans to appoint a panel of independent experts to to review the incident, and several members of Congress have called for an independent, top-to-bottom review of the agency.
"We've got to look at certain things, like, training. There's been a reduction in training. Again, morale. ... Things of that nature," Cummings said.
He said that 85 percent of all African Americans that approach him say they believe President Obama is not protected well because he is black, an idea that Cummings says he doesn't agree with.
"We have information that this goes all the way back to the Bush administration. A lot of the problems that we are talking about now, it's just that they are coming to light. A lot of these things existed before our President Obama," he said.
Cummings added that members of the president's staff have told him they feel very comfortable now that Joseph Clancy, formerly Special Agent in Charge of the Presidential Protective Division of the Secret Service, will take over the agency until a new director is appointed.