School social work began during the school year 1907–08 and was established simultaneously in New York City, Boston, Chicago and New Haven, Connecticut. At its inception, school social workers were known, among other things, as advocates for new immigrants and welfare workers of equity and fairness for people of lower socioeconomic class' as well as home visitors. These unheralded and extensive process' led to the expansion of school social work services with the encouragement of the community.
By 1900 over two-thirds of the states had compulsory attendance laws and by 1918, each state had passed compulsory school attendance laws, making school attendance obligatory by rights, and as a privilege for equal opportunity with individual differences (including differences in rate of learning). These pupil personnel workers or attendance workers were replaced by Visiting teachers by 1920s, they were later called as School based caseworkers. They made different emphases and methods in their work. E.g. Special schools, Psychosocial assessment and referrals, family based intervention ... etc.
A 1917 study of Truancy in Chicago supported "findings that the need for school attendance officers who understood the social ills of the community" and school social workers were best equipped for that responsibility (Allen-Meares, 1996, p. 25). Mary Richmond, one of the founding figures of social work, devoted an entire chapter to the visiting teacher in her 1922 book on What is Social Casework? The testing movement influenced school social work growth as well. Through the testing movement, educators were gaining knowledge about individual differences, underscoring the need for some children to attend school, children whose social conditions related to their test scores. Lastly during this time, leaders in the field like Sophonisba Breckinridge, expressed concerns of how school and education would relate to future success and happiness, and expressed the need to connect school and home in order to relate to the needs of children.
Later in the 1920s, with the mental hygiene movement school social work was concerned with treating nervous disorders and behavioral problems in difficult children and prevention of social maladjustment, this was the beginning of therapeutic role for school social workers. During the great depression in the 1930s, like school counseling, school social work also declined. Fair Labor Standards Act in 1938 a progressive movement saw social work efforts to be initiated in the schools, and community settlement programs also have its share that led to its growth.
From the 1940–1960 case work and group work in schools had become an established specialty. In 1960, pupil-personnel laws called for a greater emphasis by school social workers on the development of school policies and reforms. School social workers were affected by the governmental reforms and education research. Like guidance counselors, social workers were now called upon to address student needs while also addressing the sources of student troubles within the school. The school social worker was considered as an expert by then, who could help schools on varying psychosocial issues.
During the 1970s, school social work gave more emphasis on family, community, collaborative approach with teachers and others school personnel. In 1975, the United States passed the Education of All Handicapped Children Act (EAHC, P.L. 94-142). It gave special importance to the role of School social work services. The legislation was later renamed as the Individuals with Disabilities Education Act in 1990. In the latter part of the 1970s, inflation was rising at an alarming rate and budget cuts threatened the profession of school social work, especially as many social workers were being replaced by other school personnel claiming similar roles. The National Association of Social Work (NASW) published a newsletter to bring attention to the issue and get responses from practitioners. Through this, NASW conducted research and replicated the findings of others' studies on the roles of school social workers and models of practice, and school social work continued to expand.
In the 1980s, school social workers were included as "qualified personnel" in many pieces of legislation, especially in the Elementary and Secondary School Improvement Amendments of 1988. These led to NASW giving more attention to the profession and more service to meet the needs of the category. NASWs active participation in the profession eventually led to a school social worker credential with exams in 1992. From then until now, there has been a trend of integrative collaborative services. In 1994, school social workers were included in American Education Act. In July 1994 64 school social workers from across the country met in Edwardsville, Illinois and decided to form the School Social Work Association of America and drafted the first constitution and by-laws for the organization. In June 2009 a second national organization incorporated, the American Council for School Social Work, after reviewing the direction of the profession and concluding that a stronger, enhanced national voice would benefit the profession.
School social work in India was officially recognized by the Government of India only in the 21st century. Though, from the late 20th (1970s) century role of school social workers were prominent in elite schools, they adopted American model of specialist school counsellors, based on the client or person-centred approach of Carl Rogers and others. Central Board of Secondary Education refers school social workers as Health Wellness Teachers (CBSE Circular No.20/2014). While Integrated Child Protection Scheme strictly enforces requirement of a School Social Worker and Counselor. The programs provided under the scheme failed to address encompassing student population. E.g. Psychosocial service scheme instituted under ICPS in Kerala with the guidance of Child development center (CDC) have contracted Social Workers for 800 schools to provide the professional services. But the services limits to only teenage girls and excludes boys from equal rights to access of the program.
School social work values
Florence Poole in 1949 described School social worker as a skilled worker who is required to determine which needs within the school can be appropriately met through school social work service. School social worker must be able to develop a method of offering the service which will fit in with the general organization and structure of the school, which could be identifiable to one with social work knowledge and skill. They must be able to define the service and their contribution in such a way that the school personnel can accept it as a service, which contributes to the major purpose of the school.
The values that School social work upholds are:Each pupil is valued as an individual regardless of any unique characteristic.
Each pupil should be allowed to be participate in the learning process.
Individual differences should be recognized; intervention should be aimed at guiding pupils' goals with educational support to train them to the life to which they look forward.
Each child, regardless of race and socioeconomic characteristics, has a right to equal treatment in the school.
National Association of Social Workers, USA  has provided a model code of ethics for school social work professionals.
School social work is structured around a range of ever expanding practice models.
John Alderson was the first to describe the existed traditional-clinical models. Generally the schools followed social change model whose major focus was the dysfunctional conditions of the school; the community school model which urged school social workers to employ community organization methods; and the social interaction model which de-emphasized a specific methodology and required the worker to intervene with the systems interacting with the target system. These were known as the Traditional models. Students who have disabilities are defined as exceptional children by federal and state legislation, including the Individuals with Disability Education Act (P.L. 94-142), the Rehabilitation Act (Section 504) in the United States of America.
In the clinical model, school social workers work primarily through casework methods supplemented by group methods with students and family members; A greater emphasis is placed on evidence-based practice and promising intervention methods that is supported empirically.
Later school social workers used an approach that draws on components of the existing multidisciplinary models - Social interaction model, focusing on working with students with social and emotional difficulties and their problems in families(parents) and schools with a flexible and dynamic reciprocal interaction. This model is grounded on systems theory and transactional systems perspective. This model was an answer to organize the methodological diversity inherent in the role, rather than limiting to individual change or systems change.
Lela B. Costin, in 1973 developed this model. It focuses on the school, community, and student and the interactions among the three. In this model, school social workers serves as mediators, negotiators, consultants, and advocates for students and school personnel, listening to student grievances. They also set up informal groups for students, teachers, and other school personnel. This model also focuses on evaluation by a school social worker of the characteristics of students, the school, and community conditions and their relational affect on the availability and quality of educational opportunities to specific target groups (students with chemical dependency, disabilities, and so on). They are grounded in social learning theory and systems theory.
This model is grounded on the ecological systems theory. This was developed by Frey and Dupper (2005) and Germain (2006). The model promotes view of person and environment as a unitary interacting system in which each constantly affects and shapes the other. This model attends the complexities of the person as well as the environment by engaging progressive forces in people and situational assets, and effecting the removal of environmental obstacles for growth and adaptive functioning. This model leads to an impinging dynamic change.
The role of school social workers continues to expand as the knowledge-base, recognition of opportunities to address student need, and the level of student need grows. Two examples of this role expansion include functional behavior assessment, an efficient, empirically - supported, and amenable approach to undesirable school behavior that can be accomplished in a classroom collaboration model with teachers (Waller, 2008) and a leadership role in helping schools become foundational in promoting the mental health of children and adolescents in a manner similar to the role that schools already play in promoting physical health.
A survey published in 1989 by school social work experts categorized five job functional dimensions.Relationships with and services to children and families.
Relationships with and services to teachers and school staffs.
Administrative and professional tasks.
Services to other school personnel.
Further research on these roles revealed other important areas that are frequently addressed - Consultation and teamwork; Needs assessment and Program Evaluation; Social work interventions with systems; Developmental programs management. A role which school social worker falls short is in the range of administering diagnostic psychological tests, when in need services like IQ test, comprehensive personality tests students are referred to trained clinical or neuro- psychologist. There are one year post masters program's like post graduate diploma in clinical psychology for addressing these service issues faced by school social workers. School Social Work association of America identifies general roles like psycho-social assessment, developmental psycho-education, student and family counseling, early intervention for risk behaviors, therapeutic behavioral intervention for academic success, personality development, well-being oriented recreational therapies, yearly assessment and case management for identifying students in need of help and to promote systematic change within a school system (not to stratify students into groups and their opportunities), consultation for special issues, crisis intervention and conflict resolution.
States regulate school social work practice in different ways. Approximately 33 jurisdictions license or certify school social workers. Most require a master's degree in social work (MSW), but a smaller number of states also license Bachelors of Social Work (holders of the BSW degree). The National Association of Social Workers with 150,000 members also offers a Certified School Social Work Specialist (C-SSWS) Certificate in school social work. It is revised form of 1992 School Social Work Credential Exam. Though, it does not replace any license or certification that individual states require of school social workers. The Illinois State Board of Education requires that all students applying to an educator licensure program take and pass the Test of Academic Proficiency (TAP) and submit an ACT plus writing certificate with composite score higher than 19–22 and the same should be dated less than 10 years before submission. A passing score on the Basic Skills Test from the past 10 years will also be accepted.
The Council on Social Work Education (CSWE) is the national accrediting body for social work education at the BSW and MSW levels. It specifies foundational social work program components, but social work specialties areas are defined by the individual accredited MSW programs. "Social work education is grounded in the liberal arts and contains a coherent, integrated professional foundation in social work practice from which an advanced practice curriculum is built at the graduate level."(CSWE, Educational Programs and Accreditation Standards)
School social worker's promote student learning and well-being, address academic and non-academic barriers to learning, develop comprehensive and cohesive academic and social supports, and understand and apply diverse frameworks for evidence-based practice and program development for the educational process to work the fullest extent.
Major associations are:
- School Social Work Association of America 
- American Council for School Social Work 
- Canadian Association of School Social Workers and Attendance Counsellors 
School social work journals have been published across the globe. The oldest and largest is the School Social Work Journal sponsored by the Illinois Association of School Social Workers from Illinois, USA  another one is the Journal of School Social Work(JSSW) from Chennai, India and Canadian Journal of School Psychology from SAGE Publications, Canada.