The announcement was made at a third-anniversary celebration for their "Joining Forces" initiative at Fort Campbell, Ky.
Joining Forces mobilizes all sectors of American society to support service members, veterans and their families.
The Veterans Employment Center is designed to connect veterans and transitioning service members with employers and help translate military skills into the public- and private-sector civilian workforce.
"Our service members haven't always had the time or information they needed to prepare their resumes, to plot their career goals, to meet with employers and get the jobs they deserve. And that's simply not acceptable," the first lady said.
"As my husband has said, when you've fought for this country around the world, you shouldn't have to fight for a job when you return home.
"Starting today," she continued, "every single service member, every veteran, and every military family will have access to a new online tool that will revolutionize how you find jobs in both the public and private sectors."
The online tool is available at http://ebenefits.va.gov.
"Our service members transitioning to civilian life, as well as their spouses, deserve the resources they need to be successful," Defense Secretary Chuck Hagel said in a White House news release.
"Through this effort, they are getting that help. Our troops and their spouses are proven leaders, highly skilled and hard working. Employers hiring them are getting the best this nation has to offer."
The center is the result of an interagency effort to improve, simplify and consolidate the existing array of employment resources for veterans, officials said. It also will provide a single, comprehensive database of resumes for employers who seek to leverage the skills and talents of veterans, service members and their spouses.
The new online resource is the first interagency tool to bring together a wealth of public and private job opportunities, a resume-builder, military skills translator and detailed career and training resources.
In connection with Joining Forces, DOD and the departments of Veterans Affairs, Labor and Education and the Office of Personnel Management worked with employers to design and develop the site and incorporate features of existing online employment tools within government.
"Veterans deserve an authoritative source for connecting with employers," said VA Secretary Eric K. Shinseki. "The online Veterans Employment Center is the single, federal source for veterans looking for new career opportunities, service members transitioning to the civilian workforce, and spouses and beneficiaries looking to connect with job opportunities."
With this tool, employers will be able to search and view veteran, service member and spouse resumes in one location.
Resumes are visible to all employers with an active LinkedIn or Google profile. To prevent spam, applicants' names and email addresses are redacted, and are visible only to employers verified by VA as registered companies with the IRS. The site also is built using open data and an open application programming interface to attract private-sector innovation.
"Improving veterans' employment is an all-hands-on-deck enterprise," Labor Secretary of Labor Thomas Perez said. More than 1 million service members projected to leave the military in the coming years.
"OPM's USAJobs program is excited to be partnering with the VA on making this a robust tool for our nation's veterans and transitioning service members seeking federal employment," said Office of Personnel Management Director Katherine Archuleta.
"It has been more than four years since President Obama established the Veterans Employment Initiative, and in that time, the executive branch hired the highest percentage of military veterans in more than 20 years –- of the 195,000 new employees hired in [fiscal year] 2012, approximately 56,000 were veterans, equaling 28.9 percent of total hires," she added.
"We can continue to honor and show our appreciation for the dedicated and heroic service of America's veterans by ensuring that they have every opportunity to continue their service to this great nation as federal civilian employees, Archuleta said. "The Veterans Employment Center helps us honor these men and women by making employment opportunities available when our servicemen and women lay down their uniforms."
At today's Fort Campbell event, Biden noted the success of the Military Spouse Employment Partnership, which began in June 2011 with fewer than 60 companies.
Today, she said, the partnership has 228 partner employers, more than 1.8 million jobs posted on the MSEP Career Portal, and more than 60,000 military spouse hires to its credit.