A gay couple from Florida have become the first successful green card applicants for permanent US residency since the supreme court struck down a federal law against same-sex marriage.

Traian Popov, from Bulgaria, and American Julian Marsh learnt the decision from immigration officials on Friday as the government acted quickly to change its visa policies after last week's legal decision.

"It was just kind of a shock, like winning the lottery," said Marsh who was celebrating his 55th birthday with Popov at a restuarant when they got the news. "The amazing, overwhelming fact is that the government said yes, and my husband and I can live in the country we chose and we love and want to stay in," he told the New York Times.

Popov, 41, who has been living in the US for 15 years as a student and is working towards a doctorate in social science, married Marsh in October last year – they met in 2011. They wed in New York because Florida does not recognise same-sex marriage. Marsh, a DJ and music producer, petitioned for Popov's green card in February.

"We are first-class citizens in New York and in the eyes of the federal government, but second-class citizens in Florida," Marsh said, signalling their role as activists to change the law in Florida. "We won't stand for that."

The couple have been working with the Doma Project, which has campaigning with gay and lesbian bi-national couples, for parts of the Defence of Marriage Act (Doma) to be repealed. Lavi Solway, an attorney who co-founded the group, said: "The approval of this petition demonstrates that the Obama administration's commitment to recognising the marriages of same-sex couples nationwide is now a reality … We expect additional approvals of green card petitions in the coming days.

"It is symbolically important that the first gay couple to receive approval of their green card petition live in Florida, a state that has a constitutional ban preventing same-sex couples from marrying."

Immigration officials have been keeping a list of same-sex couples whose green card petitions were denied in anticipation of the ruling. Those decisions will now be reversed without couples having to present new applications – if no other issues have arisen.

The couple's case was not the first immigration case to be affected by the Doma ruling. Deportation proceedings against a gay Colombian man were halted by a New York immigration judge just hours after the supreme court decision.