The Committee achieved many things during its existence, including aiding in the passage of State Fair Employment Legislation and the Fair Educational Practices Act. Within New York City, the Committee did its best to promote understanding in the wake of anti-Semitic disturbances in Coney Island, the picketing of white merchants by Harlem consumer groups, and two riots in New York City high schools. The Committee also investigated city services in depressed areas of the City.

By the mid 1950s, however, it was apparent that without enforcement powers the Committee could not address problems of discrimination and bias in the City. In 1955, Mayor Robert F. Wagner and the City Council moved to replace the Committee with a city agency that had more extensive powers and permanent status. The Commission on Intergroup Relations (“COIR”) was established on July 1, 1955 under Local Law 55 to replace the original Committee on Unity.

COIR was given the power to receive and investigate complaints, and to initiate its own investigations into racial, religious and ethnic group tensions on the basis of race, creed, color, national origin and ancestry. It was empowered to hold hearings, to report its findings of facts and to make recommendations to the Mayor. COIR was also charged with studying the problems of prejudice, intolerance, bigotry, discrimination and disorder caused by intergroup tension, and developing intergroup dialogue. It also coordinated efforts among federal, state and city agencies to develop courses of instruction on techniques for achieving harmonious intergroup relations within the City of New York.

The first major expansion of COIR's powers was in 1958, with the passage of the Fair Housing Practices Law (Local Law 80, the Sharkey-Brown-Isaacs Law). This legislation, which gave COIR the power to investigate and hold hearings on allegations of discrimination in private housing, was the first in the nation to extend protection against discrimination to private housing.

In 1962, the Commission on Intergroup Relations was renamed the Commission on Human Rights. In 1965, Local Law 55 and Local Law 80 were amended and combined into Local Law 97, the Human Rights Law of the City of New York (Chapter I, Title B, later Title 8, of the Administrative Code of the City of New York). This amendment greatly expanded the Commission's powers of investigation and enforcement, and extended the Commission's jurisdiction to prosecute discrimination based on race, creed, color and national origin in employment, public accommodations and housing, as well as commercial space.

The next decade saw much growth in the Human Rights Law. The Commission's jurisdiction was expanded through successive amendments to cover disability, gender discrimination in public accommodation, reasonable accommodation in employment for religious observances, gender and marital status in housing accommodations and commercial spaces, and age in housing and public accommodations.

During the 1980s, there were many amendments to the Human Rights Law. Protection on the basis of mental disability was added in 1981. In 1984, the Private Clubs Bill, Local Law 63, prohibited discrimination by private clubs with more than 400 members. Protection on the basis of citizenship and alien status was added, and jurisdiction over housing discrimination was extended to include protection of lawful occupation and persons with children. In 1986, landmark legislation extended coverage of the Human Rights Law to include sexual orientation.

In 1991, the Human Rights Law was extensively revised and amended. For the first time protection in employment on the basis of conviction or arrest record was enumerated in the Administrative Code. In addition, the amendments broadened liability and they afforded new protection for individuals retaliated against for opposing discrimination.

In 1993, the Human Rights Law was amended once again to provide remedies for bias-related harassment.

In 2001, status as a victim of domestic violence was made a protected class with regard to employment.

In April 2002, the City Human Rights Law was amended by defining “gender” to include actual or perceived sex as well as a “person’s gender identity, self-image, appearance, behavior or expression, whether or not that gender identity, self-image, appearance, behavior or expression is different from that traditionally associated with the legal sex assigned to that person at birth.”

In December 2003, the City Human Rights Law was amended once again protecting victims of domestic violence, sex offenses and stalking in the workplace. The Law requires all employers provide reasonable accommodation to victims of these crimes.

In October 2005, Mayor Michael R. Bloomberg signed Local Law 85, The Local Civil Rights Restoration Act of 2005, into law. This amendment to New York City's Human Rights Law was meant to ensure that the rights of those who live, work and play in New York City will continue to be protected by the strongest civil rights law in the country, despite recent state and federal court decisions diminishing the impact of groundbreaking civil rights legislation and 50 years of precedent.

The changes include a statement that state and federal law are the minimum standards to be applied when analyzing cases under the City's Human Rights Law, a clarification that an adverse impact is not required in retaliation cases, and an indication that a plaintiff whose action was a catalyst for a change in policy may be considered a prevailing party for the purposes of awarding attorney fees in state or federal court. In addition, among other things, the amendment added "partnership status" as a protected class under the law, requires the Commission to conduct "thorough" investigations and increased the penalties that the Commission is empowered to access.

The New York City Human Rights Law was amended by the City Council in March 2008 to make ‘any lawful source of income’ a new protected class. This amendment prohibits landlords from discriminating against tenants based on the fact that they receive federal rent-subsidy vouchers or other government assistance to pay their rent.