Gathering with family and supporters inside Grand Central Terminal, where he first launched the organization to help homeless people get back on their feet, McDonald said the city is at a crossroads.
"This is the most important election in 20 years," said McDonald, who is facing a potentially crowded field that could include former MTA Chair Joseph Lhota, former Bronx Borough President Adolfo Carrión, supermarket magnate John Catsimatidis, Brooklyn mega-church pastor Rev. A.R. Bernard, and Manhattan Media CEO Tom Allon.
"There are those who want to harken back to the divisive policies of the past. And there are those who would turn our city back over to the union and the special interests," he said, presumably referring to the Democratic field.
"Under the wrong leadership," he warned, "all we have done to make our city better can come undone."
His platform, he said, will focus on making sure that all New Yorkers are put to work.
"We face a jobs crisis in our city," he said, pointing to an unemployment rate as high as 11.8 percent in the Bronx.
"The central promise of the McDonald administration is simple: We must set as a goal the full employment of every resident of our great city," he said. "Every New Yorker who wants a job should have a job."
McDonald, who switched his party affiliation this summer when many were still expecting a weak Republican field, also tried to distance himself from failed GOP presidential candidate Mitt Romney.
"I know something about the 47 percent. I have worked with them each and every day for the past 25 years. They don't dream less. They don't care less, they don't aspire less," he said, in a shot against Romney's comment that 47 percent of Americans were simply looking for handouts.
"A McDonald administration will work for 100 percent of New Yorkers," he vowed.
In response to a reporter's question, McDonald said that he had, indeed, voted for Romney, but added: "That doesn't mean that I agreed [with him] on everything."
McDonald was introduced by DOE Fund security director Louis Napolitano, a former transit officer who had once arrested McDonald for distributing food to the homeless at the station.
After the event, McDonald, trailed by a gaggle of press, headed around the corner, where he began introducing himself to hundreds of people waiting in line to enter a job fair sponsored by the website TheLadders.com.
"I liked the vibe. It was a positive energy," said Samuel Semple, 28, who said he's been unemployed for about a year.
He said he liked McDonald's focus on putting people back to work.
"That's a great message," he said.
But Josh Friedman, 31, who was looking for help landing a new position, said that, while he didn't know enough about the candidate to dismiss him outright, after nearly 20 years of Bloomberg and Giuliani rule, he felt it was time for a change.
"Why do you care about helping all these business groups that already have a lot of help?" he asked. He said he was leaning toward voting for a Democrat.