[3] Her career in social reform began as a young girl with the Temple Israel Sisterhood who collected money, organized sewing for the poor, and worked with United Hebrew Charities.

As Belle Israels, her first effort at social reform was to clean up and license the city's commercial dance halls, which she saw as places that got young working girls into trouble.

Working through the Council of Jewish Women-New York Section, by 1910 she had won laws that regulated dance hall conditions, including fire and safety and the selling of alcoholic drinks.

The New York Times stated, "These laws did more to improve the moral surroundings of young girls" than any other single social reform of the period.

Also with the Council, Moskowitz initiated a program for reform to make dance halls a safer space for young women, particularly "working girls", by controlling alcohol distribution.

[7] She advised him throughout the process of enacting broad reforms for the state of New York that would later inspire and direct Franklin Delano Roosevelt in the development of the New Deal during his presidency in 1932.

[3] During her time working with Al Smith, Moskowitz mentored a young Anna M. Rosenberg in the art of wielding power behind the scenes.

[10] She met her second husband, Henry Moskowitz, who had a Ph.D. in Philosophy and was a settlement worker on the Lower East Side, while working with him on dance hall reform.

Their paths crossed many times during the tumultuous garment strikes of the era, and they worked together on the investigations that followed the Triangle Shirtwaist Factory fire.

On December 8, 1932, she fell down the front steps of her house and, while recovering from her broken bones, died of an embolism on January 2, 1933, at age 55.