The team are also the reigning World Champions after winning Rugby World Cup Sevens in Moscow in 2013 and won the silver medal in Rio last month, losing to Australia in the final.
Horan came to the role when New Zealand Rugby launched the Go4Gold programme which aimed to attract women from all sports in order to build a strong national sevens team.
"We fell short of our goal in Rio, but we shouldn't lose sight of what we've achieved. We've built a strong platform for the future and that's a credit to the hard work our players and management have put in over the years.
"Our vision was always to inspire young women to wear the black jersey and be very proud and I think we did that. The game now is huge. There are many clear pathways for young women to embrace sevens and aspire to wear the black jersey.
"It's hugely satisfying to have been part of this great adventure right from the beginning," he said.
"We started with a blank canvas and built a great team in a short period of time. I leave knowing my successor will come to the job with a strong high performance programme established.
"We've nailed much over the past five years. I really hope what this team has done inspires a new generation of players who see sevens as an exciting option."
The former Bay of Plenty Steamers coach said he would now take a break from the game and consider some options.
"I love rugby and fully intend to keep involved in some shape or form, but now's the right time for someone else to take up the sevens reins and build on the strong foundation the team's created."
New Zealand Rugby will shortly advertise for the new Black Ferns Sevens coach.
The four-year appointment will be through to the next Olympic Games in Tokyo in 2020.
