FFA chairman Chris Nikou announced on Thursday that Gallop would leave the organisation on 31 December.
The former NRL CEO has been criticised often since being appointed by FFA in 2012, but Nikou paid tribute to Gallop in a statement.
"David has provided strong and distinguished leadership over a long period and particularly through a difficult last few years for FFA as we have managed the governance and structural changes around the game," he said.
"Working together for the next six months, we will continue to reposition FFA for ongoing success. While he will be with us for some time yet, David will leave us with our respect and sincerest best wishes for continued success in the next stage of his career."
It was announced on July 1 that an in-principle agreement had been reached to establish independence for the A-League, W-League and Y-League.
Gallop said that would lead to changes for the FFA CEO, but he was pleased with some of his achievements.
"It has been an honour to lead FFA for the last seven years. Football is the true world game and many Australians from all backgrounds want to see it grow bigger and stronger in the decades to come. From the Caltex Socceroos and the Westfield Matildas to the vast participation base of men, women, boys and girls who love to kick a football there are so many wonderful ways to enjoy the sport," he said.
"With the NLWG [New Leagues Working Group] recommendations to bring about fundamental changes to Australia's professional competitions – the Hyundai A-League, Westfield W-League and Foxtel Y-League [the Leagues] and FFA, the chief executive's role as it currently exists will be a very different, narrower role. It makes sense for everyone to have time to openly determine what that new role and new leadership looks like.
"It has been very satisfying to be part of so many important moments including the introduction of the FFA Cup, winning the AFC Asian Cup, participating in the FIFA Women's World Cup & FIFA World Cups, securing a record six-year media rights deal with Fox Sports, strengthening the financial aspects of women's football, adding expansion teams to the Hyundai A-League and growing the huge participation base of the game.
"There are challenges given the expectations that are created by the global mirror that is held up to the game in this country's competitive sporting landscape, but enormous growth opportunities are available if the stakeholders are united."