The term ‘principal’ usually denotes the administrative head of a public or private school responsible for instructional, supervisory, fiscal, and facilities responsibilities. In the US context, most public school principals are appointed by the local school district board and are supervised by the superintendent or a deputy at the district level. Private school principals or headmasters are appointed and supervised by a school board or committee.

The principal’s role has acquired greater importance recently as research confirms an indirect, but significant influence of the principal on student achievement. This indirect influence occurs through the principal’s actions in creating a supportive climate for teachers and students, establishing structural arrangements to facilitate teaching and learning, and providing relevant professional development.

The origin of the principalship is not completely clear but several factors seem to have influenced the development of what was originally called the ‘principal teacher’. These factors include evolution from teaching; emphasis on religious practices to embed national values; acquisition of management responsibilities, including middle-management roles between school and district office; changing demographics involving population growth, urban development, and diversity; and professionalism.

Over time perspectives on what principals were expected to do changed. These changing perspectives primarily included movement from an emphasis on management to instructional leadership, political environment changes (legislative and judicial demands), increasing complexity, and increasing professional standards and licensure. Researchers differ in whether they claim change or constancy in the role.

US principals tend to be female, around 50 years old, White, and hold masters degrees. While there are some differences between public and private school principals as well as between elementary and high school levels, these averages are similar. Some changes in principal characteristics have occurred over time, including a slight increase in Black and Hispanic principals, teaching experience, and salary.

A description of the work of school principals includes tasks, dispositions, values, beliefs, and identities. Research has found that principals spend most of their time on internal administrative tasks followed by curriculum and teaching related tasks, student interaction, and parent interaction. This varies somewhat with elementary principals who spend more time interacting with students. Research has also found a relationship between principal practices and student achievement. Principals in lowest performing schools tend to spend more time on administrative tasks, whereas those in highest performing schools tend to spend more time on day to day instruction. Organizational management (e.g., managing resources, maintaining facilities, dealing with staff concerns, hiring personnel) tends to be associated with both student performance and student improvement. The four primary tasks associated with success as a principal include building vision and setting direction, understanding and developing people, designing organization, and managing teaching and learning programmes.

In addition to tasks, principals bring dispositions, values, and beliefs to bear on their work. Traits and dispositions such as cognitive abilities, personality, motivation, and social appraisal skills and values such as respect for others, honesty, role responsibility, and belief in the participation of all stakeholders are related to principal work, especially for successful principals.

The meanings that principals attach to their roles, i.e., identities, are critical for motivating and providing the rationale for what principals do. Although there are different ways to characterize principal identities, several are based on empirical and conceptual research: principal as learner, culture builder, advocate, leader, mentor, supervisor, manager, and politician.

Although the principalship has various factors, e.g., middle-management role, that encourage constancy in the role, there could be areas for change. These include whether the job needs to be performed by more than one person, increasing diversity of occupants in the role, and preparing principals for greater complexity in the role.