Among the expected changes is non-discrimination against a military applicant who may volunteer that he or she is gay, opening the door to the return of thousands of service members whose careers were cut short after they were outed on the job.
"I just really miss it. I miss the people, the mission, the comraderie. I can't wait to get back in there and finish my career," said Mike Almy, an Air Force Major and 13-year veteran who was discharged four years ago after investigators learned he was gay through personal e-mails. He plans to re-enlist.
Nobody knows for sure how many of the estimated 14,000 gays and lesbians discharged because of their sexual orientation will want to re-enlist or still meet the requirements for active duty, including age and fitness levels.
But some advocates estimate up to a quarter of those discharged under "don't ask, don't tell" could return to the force.
"We expect that all who are otherwise qualified will be allowed to rejoin and at least pick up their careers where they left off," said Aaron Tax, legal director for the Servicemembers Legal Defense Network, who said many gay veterans were interested in continuing to work toward 20 years of service to earn valuable military retirement benefits.
Jason Knight, discharged after five years as a Navy Hebrew linguist, said he plans to re-enlist as soon as he can because there is such high demand for interpreters and intelligence analysts.
"Linguists have the highest security clearance and are essential in deciphering foreign intelligence," he said. "And anecdotally at least, they are the biggest field hit by 'don't ask, don't tell' next to pilots and medics... I'm going back to reach my 20 years of service and retire."
An estimated 800 mission-critical troops, including at least 59 Arabic and nine Farsi linguists, have been fired for being openly gay between 2003 and 2008, according to estimates provided by the Pentagon to SLDN.
A Pentagon study released earlier this month found that there would be minimal risk to military effectiveness in enacting a repeal.
Fifty to 55 percent of those surveyed said the repeal wouldn't have any effect, 15 to 20 percent said it would have a positive effect and 30 percent said the effect would be negative. The report also concluded that encounters with gay service members are common.
Obama, Chairman of the Joint Chiefs of Staff Adm. Mike Mullen and Defense Secretary Gates all had called for a repeal of the policy.
Four GOP senators voted in favor of repeal -- Susan Collins and Olympia Snowe of Maine, Scott Brown of Massachusetts and Lisa Murkowski of Alaska.
The most recent ABC News/Washington Post poll found 77 percent of Americans support allowing gays and lesbians to serve openly in the U.S. military, the largest show of support in the history of the policy.