Uber has reached its goal of signing up 50,000 U.S. military veterans as drivers on its platform. And it is celebrating by donating $1 million to an assortment of organizations that help veterans and their families.

The announcement Thursday is the culmination of work that began back in September of 2014, when the company launched UberMilitary. One of the goals of the campaign, Uber wrote in a blog post at the time, was to work with veterans and "empower them as entrepreneurs and small business owners."

So far roughly half of the 50,000 veterans and their spouses who have signed up to drive for Uber have actually completed a trip. It's a figure Uber is proud of, and which seems to be higher than the conversion rate of the general population, or of similar campaigns such as Uber's partnership with AARP to sign up retirees.

The donation marking the milestone will go to the U.S. Chamber of Commerce Foundation's Hiring Our Heroes, Tragedy Assistance Program for Survivors, Iraq and Afghanistan Veterans of America, and Homes for our Troops. The funding comes directly from Uber's coffers, and is being allocated to those organizations based on recommendations from the company's UberMilitary Advisory Board, which includes former Defense Secretary Robert Gates.

What's the connection between Silicon Valley's most highly valued startup and the U.S. military? Heading up the UberMilitary endeavor is Uber vice president of business Emil Michael, who formerly worked for the Defense Department as a special assistant to Gates. He's also a member of the Pentagon's Defense Business Board, which The Wall Street Journal describes as "an advisory group tasked with sharing best practices from the private sector with an agency straining at the leash of its half-trillion-dollar annual budget."

While working for Gates in between jobs in Silicon Valley, Michael visited Walter Reed Medical Center, and took trips to both Iraq and Afghanistan. He says he learned a great deal about the life of a soldier, and the intense challenges of returning home after serving one's country.

"When I got back into the private sector, I racked my brain for how to give back to vets," he said. "Vets don't want a handout. They want to work. And Uber fits what they need, because it can easily be part-time or fill out those transition times. "

Michael is essentially the top voice at Uber for developing partnerships and conducting fundraising, both of which the company has been extraordinarily successful at recently. But he's been keeping a fairly low profile in the press over the past year and a half. If you've heard of him before, it's probably because around the time UberMilitary was starting up, he reportedly suggested Uber spend $1 million hiring opposition researchers to dig up dirt on journalists who'd written critical stories about the company.

Over the past 18 months, he's found a--let's just say--far friendlier way to spend $1 million.

"In general Uber is a place where as an employee you get to pursue your passions. Helping veterans is something I've been passionate about," Michael says. "This was one of the proudest things that I've done at Uber."

Another component of the UberMilitary announcement includes beefing up Uber access on military bases in the United States. Due to security screenings at their entrances, military bases are a tricky destination for taxis and other car services. For service members, that makes for a lack of reliable transportation. "We could probably alleviate the drinking and driving problem that arises," Michael says.

Not just kittens anymore

Robert Isaac Jr., is one of the program's success stories. Isaac, who left the Marine Corps in 2004 after serving in Kuwait, Baghdad, and Jordan, first encountered Uber in the San Francisco area, where he'd hail a ride now and then. And when he wanted to take a costly class to learn user-interface design, he signed up with Uber to earn money to pay for it.

"The appeal at first was having the flexibility to make extra money: A second job without a second boss," he said. Soon, he was earning enough on Uber to quit his first job in order to study more. (According to the company, 77 percent of military-veteran drivers say Uber is their second source of income. Drivers in the program have taken home a total of $130 million over the past 18 months.)

Interestingly, the UberMilitary initiative is far larger than most of the company's other charity efforts. With a presence in 68 countries and more than 400 cities around the globe, Uber tends to work with a lot of local charities, and the partnerships are small. (Consider the little partnerships with groups like the ASPCA on cuddly promotions such as "Uber Kittens," where drivers ferry kittens to places of business-- and hopefully find homes for a few of the furry orphans.)

Uber has a director and a couple full-time staffers working on the UberMilitary initiative. Roughly 50 Uber employees in cities around the country also work on the project as part of their duties.

UberMilitary's goals for the next few years include making sure veterans and their spouses who drive for Uber collectively take home $500 million, offering greater incentives for veteran drivers, and further increasing access to Uber on military bases.