Israel Kugler was a noted advocate for and leader of academic unionism, professor of sociology, labor arbitrator, democratic socialist activist and devotee of Yiddish culture. Born in Brooklyn, New York, he received his bachelor's degree from City College in 1938. He married Helen Barkan in 1941 and they were to have two sons, Daniel and Philip. After serving in the Navy during World War II, he earned his M.A. and Ph.D. in sociology from New York University in 1954, writing a dissertation on the relationship between the mid-nineteenth century women's suffrage movement and the National Labor Union. In 1947 he was appointed a faculty member in social science at New York City Community College (now New York City College of Technology), where he taught until 1980.

Kugler was a key figure in the United Federation of College Teachers (UFCT), which originated as a section of the Teachers Guild and later the United Federation of Teachers and became Local 1460 of the American Federation of Teachers (AFT). The UFCT represented faculty and professional staff in both public and private institutions of higher education. Kugler had served as vice-president of the Guild/UFT section from 1954 and became president of the UFCT in 1963. Within a few years Kugler had led successful organizing organizing campaigns at Fashion Institute of technology, Long Island University, Pratt Institute and several other campuses.

During the mid-1950s, Kugler led a group which advocated that the AFT adopt a resolution which would suspend the charters of segregated locals. This resolution was adopted by the AFT in 1955.

In the fall of 1965, 31 faculty members at St. John's University in Queens (then one of the largest Catholic universities in the world) were notified of their dismissal or contract termination as of the end of the academic year, without any charges, hearings or other form of due process. Kugler led a faculty strike which began in January of 1966, and included not only demands related to the dismissed members, but also issues of salary and benefits. It was the first strike in the United States by the faculty of a four-year institution of higher education. The strike lasted until June 1967, when St. John's agreed to arbitration. Although the St. John's strike did not result in reinstatement of the faculty or official recognition of the union, it did establish the AFT as a leader in the unionization of faculty and staff in higher education.

In 1972 Kugler, along with Belle Zeller, president of the UFCT's long-time rival, the Legislative Conference, finally concluded the hard-won merger of the two organizations into the Professional Staff Congress (PSC), a unified representative body (and bargaining agent) for faculty and technical staff at the City University of New York. He served as the Deputy President of the PSC from 1972 until 1973.

Beginning in 1977, Kugler frequently served as a labor arbitrator; he was a panelist with the American Arbitration Association, the New York State Mediation Board and the National Mediation Board, among others. He also served as president of The Workmen's Circle, a national Jewish fraternal organization, from 1980 until 1984.

He was affiliated with many organizations, including the Three Arrows Cooperative Society, the League for Industrial Democracy, the Jewish Labor Committee, the Industrial Relations Research Association, Social Democrats, USA and the Forward Association. In June 1997 the New York City Technical College and the City University granted him an honorary doctorate in Humane Letters.