Liuba Grechen Shirley, a 36-year-old mother of two, submitted a request with the FEC early last month. She told ABC News that the process went smoother than she had expected.
"I was expecting to testify today and to answer questions, but was thrilled with their unanimous vote," Grechen Shirley said.
Though Grechen Shirley said "the overwhelming response has been support," not all feedback has been positive.
Grechen Shirley's opponent in the upcoming June 26 Congressional primary for New York's 2nd District, fellow Democrat DuWayne Gregory, was critical of her request to use campaign funds for childcare.
"It's disappointing that my primary opponent can't support something as critical as childcare," Grechen Shirley said of Gregory, who said Thursday he's glad the issue has been put to rest.
"It was not an approved expense," Gregory told ABC News. "But now it is, so certainly, as long as it's within the guidelines of the FEC, I'm fine with it."
Gregory said that he has been mischaracterized, noting that he was named "childcare advocate of the year" in 2013 by the Child Care Council of Suffolk.
"It's politics, I get it," Gregory said.
Grechen Shirley said that several skeptics have come around to her side.
"There have been a few people who have had concerns," Grechen Shirley said. "Some people thought that these funds were taxpayer dollars, and when they realized that these were funds that I am raising for our campaign they were fine with it."
As a countervailing force to critics, a letter of support was submitted to the FEC by 24 members of Congress on Tuesday, and another on behalf of former Secretary of State Hillary Clinton last month. The latter took Grechen Shirley off guard.
"My campaign manager called me on a Friday afternoon, and it was an incredible surprise," Grechen Shirley said. "I had no idea that was going to happen."
The FEC's decision hinged on Grechen Shirley's childcare expenses not being deemed "personal use," defined as costs that "would exist irrespective of the candidate's election campaign." Campaign funds would not be allowed to pay for such "personal use" expenses.
"The Commission concludes that your authorized campaign committee may use campaign funds to pay for the childcare expenses described in your request because such expenses would not exist irrespective of your candidacy," the FEC's opinion stated.
While Grechen Shirley has touted Thursday's opinion as a "game changer," it is not clear whether it has set an entirely new precedent, as the FEC made a similar decision over two decades ago.
"The Commission has previously considered the permissibility of using campaign funds to pay for certain childcare expenses in more limited circumstances," the opinion read, referring to a 1995 decision that granted a male candidate permission to use campaign funds for "occasional childcare" expenses.
"The fact that you seek to use campaign funds to pay for more than the 'occasional' childcare expenses approved of in Advisory Opinion 1995-42 (McCrery) does not change the relevant question, which is whether such expenses would exist irrespective of the candidate’s campaign or officeholder duties," the opinion stated.
Regardless, Grechen Shirley hopes her victory will encourage many more women to run for office, especially those for whom childcare is a financial barrier to entry.
"I wouldn't be able to do this," she said of her own campaign.
Even with her babysitter's fee covered (around $440 per week to watch her 2-year-old son and 3-year-old-daughter), Grechen Shirley said it's "an interesting juggling act" being both a candidate and a mom.
"I'll run home from events and do bath time and dinner and get them to bed, and then run back out to events," she said.