It has ambulatory practices throughout the five boroughs of New York City, Westchester County, and Long Island, along with more than 30 affiliated community health centers.

[4] In the 2017–2018 fiscal year, the Health System employed more than 39,000 people and the Icahn School of Medicine at Mount Sinai had 33 multidisciplinary research, educational, and clinical institutes.

[7][12] On January 9, 1997, St. Luke's-Roosevelt entered into a partnership with Beth Israel Medical Center forming the Greater Metropolitan Health Systems, Inc.

[15] Continuum Health Partners provided subscribers with a form to request that Aetna retain their physicians for one year or until the policy period ended.

At the time, Mount Sinai officials admitted to partial misconduct and offered to cover limited billing claims retroactively.

[18] In 2017, Mount Sinai West entered into settlement concerning the improper disclosure of patient medical records which was settled as the payment of a levied fine of approximately half-a-million dollars as reported in the medical journal Becker Hospital Review stating: "New York City-based St. Luke's-Roosevelt Hospital Center (Mount Sinai West) will pay $387,200 and implement a corrective action plan as part of a HIPAA settlement to resolve allegations it inappropriately handled a patient's sensitive health information.

Mount Sinai and the four named men are accused of allowing a range of illegal activities, including acting "abusive, dismissive and hostile" to and discriminating against women, especially older women; verbal abuse of women; lying to financial donors such as USAID; misallocating funds; giving preferential treatment and higher salaries to men; failing to obtain Institutional Review Board approval prior to conducting research in violation of federal guidelines; failing to comply with the Health Insurance Portability and Accountability Act or HIPAA.

In May 2019, more than 150 students at the Icahn School signed a letter, addressed to the Board of Trustees, calling on Mount Sinai "to further investigate allegations of gender and age discrimination" as a result of the legal filing.

[24] In January 2016, Mount Sinai launched their first nationwide print and television advertising campaign focused on promoting their network of hospitals, ambulatory practices, community health centers, and affiliations beyond the state of New York.

[26] In 2019, the health system launched a television advertising campaign linked with an offline Long Island Rail Road, Metro-North Railroad, and New York City Subway awareness during the 91st Academy Awards.