The agency, which has offices in New York, London and Sydney, will immediately start working with the sports club as a consultant and partner on a number of targeted fan activation and engagement projects.
Jonny Bauer, the chief strategy officer at Droga5, said: "As an agency of people who both live for football and love New York, the branding and launch of our city’s first MLS team is a dream project.
"We’re looking forward to working hand in hand with our NYCFC partners to give New York football fans something to get excited about, and all New Yorkers yet another source of pride."
The New York team was established as a $100 million (£63 million) joint venture between Manchester City Football Club and the New York Yankees baseball team.
NYCFC was officially announced as Major League Soccer’s 20th team in May this year.
Speaking about the new partnership, NYCFC’s chief executive, Ferran Soriano. said: "In Droga5 we have found the ideal partner to help us establish and grow New York City Football Club. They share both our passion for soccer and our belief in innovation and creativity.
"While they have a global perspective, they are also locally rooted in New York, ensuring proper understanding and communication with our fans in this great city. We are looking forward to working together."
Earlier this week, Campaign revealed that Tamsin Davies, a strategist from the Nike Foundation and previously a planner at Fallon London, would join Droga5 London as part of Toto Ellis’ strategy team.
The agency counts among its clients American Express, the Coca-Cola Company, Unicef and Spotify.