"Sen. Sanders is a long-time friend of Rev. Jackson. They held a very productive, hour-long meeting at Operation PUSH headquarters on important issues confronting the country and the African-American community," Michael Briggs, Sanders' campaign spokesman, said in an email to CNN.
Jackson tweeted about the meeting on Monday, noting that Sanders' wife, Jane, joined the gathering.
"Meeting today with @SenSanders and wife today @RPCoalition Headquarters," he wrote.
In a phone interview with CNN on Tuesday, Jackson said the meeting was "meaningful" and made clear that Sanders is interested in addressing voting rights, urban reconstruction and the impact of racism on black people.
Jackson said Sanders "understood" the issues that the civil rights leader brought up.
"I think the more he talks to people directly the more they will be able to appreciate what he has to say," Jackson said. "He comes from Vermont. This is different than say Bill Clinton coming here from Arkansas."
Jackson said he did not endorse Sanders in the meeting and is interested in meeting with other Democratic contenders before he makes his selection. Jackson said he has "tremendous respect" for Hillary Clinton, but has only talked to her staff so far, not her. But the civil rights leader did defend Sanders against critics who have called his run "fringe."
His advice to Sanders: Define socialism "in a way that takes away the label they are trying to put on him."
Too many people, Jackson said, "dismiss his campaign as just an angry margin. The fact is... this is mainstream."
Jackson and Sanders have history together: The independent senator endorsed Jackson's failed 1984 and 1988 presidential campaigns.
Since launching his presidential campaign earlier this year, Sanders has been dogged by questions about his ability to effectively advocate for criminal justice reform and win over African-American voters. Protestors from Black Lives Matter, a nationwide movement focused on the death of African-American men and women at the hand of police, ended a Sanders appearance earlier this month
in Seattle and have protested a handful of other events.
Sanders' campaign has tried to address the issue. The candidate has worked race and justice issues into nearly every speech he gives, and the campaign has hired Symone Sanders, a young African-American woman, as their national press secretary.
Representatives from the campaign have also reached out to Deray McKesson, an influential Black Lives Matter activist with a large social media presence, about setting up a meeting.
".@BernieSanders, the first draft of your racial justice platform has promise," McKesson tweeted on Monday. "When will you be available to discuss enhancements w/ folks?"
Sanders account responded: "@deray Let's do it. We will PM you this week to arrange."
Briggs would not confirm when the meeting with McKesson would happen, but said the campaign is working to schedule meetings with "many different people."
After having his speech shutdown by Black Lives Matter in Seattle earlier this month, the campaign also added a "Racial Justice" tab to their campaign issues page.
"We must pursue policies that transform this country into a nation that affirms the value of its people of color. That starts with addressing the four central types of violence waged against black and brown Americans: physical, political, legal and economic," the website reads.
campaign has also reached out to McKesson and other Black Lives Matters activists, according to an aide. The campaign organized a conference call a few weeks ago for McKesson, Brittany Packnett and other activists to chat with Maya Harris, Clinton's senior policy adviser. The activists had specifically asked to speak with a policy adviser, Clinton aides said.