The Partnership for New York City, an influential business advocacy group, announced on Monday that Mayor Steven Fulop of Jersey City would take over the organization as its next leader.

The role has been held for more than two decades by Kathryn S. Wylde, a power broker who has shaped mayoral administrations, public policy and the influence of New York’s business class.

Ms. Wylde announced in May that she would step down after the partnership had found a replacement, ending a career there that began in 1982, a few years after David Rockefeller formed the group as a voice of the business community following New York City’s fiscal crisis.

Today, the partnership represents more than 300 companies, including some of the biggest firms in finance, media, real estate and technology like Google, JPMorgan Chase and Verizon. Collectively, the companies employ more than a million people in the city.

Mr. Fulop will become the organization’s president and chief executive early next year, just after his third term as mayor ends.

In public and behind the scenes, Ms. Wylde, 79, has warned of anti-business rhetoric that she says drives away development and jobs, and she has championed the benefits of the city’s corporate giants and their wealthy business leaders, including the taxes they pay.