In late February, a leader in the Black Lives Matter movement made national news by jumping into the mayor's race in Baltimore. Not only was he an unlikely candidate, he filed to be one with just one minute to spare.

DeRay Mckesson, a Baltimore native and Teach for America alum, is paradoxically a national celebrity with more than 300,000 Twitter followers and a candidate who has little support among voters in Baltimore. (He polled below 1 percent last week.)

Baltimore's Democratic primary is April 26, and it likely will decide who the city's next mayor will be. (The Democratic nominee in Baltimore has won the city's general election since the 1960s.) The incumbent, Mayor Stephanie Rawlings-Blake, isn't seeking re-election, prompting a crowded field to campaign for the open position. 

Mckesson recently spoke with Governing about what he's learned since transitioning from an outsider criticizing the mayor to a candidate vying for her job. The following transcript has been edited for clarity and length.  

You got into the campaign late in the game. How are you trying to catch up with candidates who have been in the race since last year? 

My campaign is explicitly about the details. It's not about broad promises and platitudes. The format of the forums privileges the 90-second repetition of the problem, which is disrespectful to people's lives. The moderator will say, "How do we make policing better?" Then the candidate will say, "Well, the police need to be better. People want them in their communities and we have to think about how to do that." That's different from saying, "I'm calling for expanding the consent decree [with the U.S. Justice Department] to include school police and to take back the Memorandum of Understanding that says when police kill people they don't get drug tested." These are the things they could actually do.

I would think that if you were to surge and win this race, it would have to be by engaging in a different part of the electorate that doesn't typically participate in a Baltimore mayoral primary. How are you going to drive turnout beyond what we've traditionally seen in these primaries?

I can't give away my secrets. [laughs] What I can say is that none of us actually know what turnout is going to be this year because we've never had the mayor's election aligned with a presidential election. We are all guessing. We don't know what Bernie plus Hillary will do to make people who don't vote come out to vote.

When you made your initial announcement, you seemed to be going out of your way to clarify that your candidacy was not going to be purely about policing and crime. You referenced the environment, education and public health, for instance. Could you walk me through your thinking there?

This is about our whole city. Talking about the whole city means we have to talk about the environment and arts and culture and tech and infrastructure. We have to talk about all these things. What impacts most people are crime, safety and schools, but we are also rapidly losing green jobs and that the sewer pipes need to be replaced and we have 70,000 people addicted to substance abuse. To be a mayor, you should actually have to talk about all these things.

Do you object to being characterized as "the Black Lives Matter candidate"?

I'm one of many. This work will require that people continue to push from the outside and also require that people push from the inside. I am one of many people who stood in streets to demand that government be different. I will likely be one of many people who run for office to make government different, to make it just and equitable and to do concrete things that will impact people's lives positively. I don't think I'm the only one. I don't think I'll be the only one.

You're 30 years old. What's your pitch to people who think your age is a reason not to vote for you?

There are traditional pathways people have taken to become a candidate. What we know is that those people and those pathways is exactly how we got here. In the latest poll, one of the things that we found is that a quarter of the electorate is still undecided. Even more people than that are persuadable. The same old, same old is what got us here and what has never proven to get us out of here.

Is there anything about your experience as a first-time candidate that has surprised you?

The fundraising. I understand the need for campaign finance reform in a way that I did not before. The fundraising work takes a significant amount of time and it's hard work. In Maryland, companies can give money, too. It privileges developers who can give $6,000 as a person and their company can give $6,000 and their other companies can give as well. I've seen that actually happen in real time. The vast majority of my donations are individual donors. The aggregate is an important sum, but other candidates have significantly fewer donors who are maxing out with every company they own. The need for reform is real.