In the United States, the field of education falls into four main divisions: preschool, elementary education, secondary education, and postsecondary education. In each of these divisions, the largest population of employees is made up of teachers. Other primary employees in each division are teacher assistants and school administrators.

Teachers of younger children perform many of the roles of a parent, so the jobs of the preschool, kindergarten, and elementary school teachers include the personal and social responsibilities that are assumed by parents at home. These jobs, of course, include the full gamut of responsibilities for the emotional and intellectual growth of children. Responsibilities of teachers of grades K–6 include teaching, selecting and planning course work, grading homework, and evaluating student achievement. They participate in conferences with parents, other teachers, and administrators on problems with curriculum, instruction, and guidance. They meet with social workers and psychologists regarding students with mental, emotional, behavioral, physical, or learning disabilities.

High school teachers have basic responsibilities similar to those of elementary school teachers, but they act less as parent substitutes and are more concerned with academics. Typically, high school teachers specialize in one or two subjects. But even at the high school level, teachers are concerned about more than the students' academic progress. They help students deal with personal problems and advise them in matters concerning their future, such as selecting colleges and careers.

Similar to the high school teacher, the college professor shares the commitment to a specific field of knowledge, but such commitment is more intense. College professors are expected to participate in the activities of a professional society or association. Increasingly, professors are sought out as consultants in business, government, and public service. With more demands on their time outside of the classroom, college teachers have less time to spend with students than they would like. Professors with years of experience and a high level of specialization may choose to teach at the graduate level. These teachers spend more time in research activities and work with a small number of graduate students.

Teachers use a combination of traditional resources and recent innovations to educate students. Many schools still feature blackboards, and students still use textbooks, paper notebooks, and pens, pencils, and other writing tools. Depending on the schools' budget, teachers also use computers, mobile devices such as tablets and smartphones, as well as interactive whiteboards that project data from computers. They share information and lesson plans with students and parents via e-mail and through Web sites.

A variety of new opportunities for educators have evolved in nontraditional areas. Qualified education professionals are needed to work in agencies such as adult education programs, recreation departments, drug and alcohol abuse programs, Planned Parenthood units, and government organizations such as the Peace Corps and Job Corps. Teachers are finding more opportunities in business, vocational, and special interest training, where a degree in education is not as important as work and life experience.

Teachers may work for public school systems or private schools. Preschool teachers also have the option of providing some day-care services in the home. Charter schools have gained popularity in the 21st century. According to the National Center for Education Statistics, in the 2015–2016 school year, approximately 2.8 million students attended charter schools, an increase over the 2.1 million charter school students enrolled in the 2011–2012 school year. At many of these schools, educators are encouraged to try new methods and models.

Thousands of people are employed by professional organizations, private agencies with educational programs, and government offices of education. Every state in the United States has an office of education, which hires professionals to monitor and make recommendations for local school policies. The federal government also employs professionals to ensure that legislative mandates regarding education are carried out at the state and local levels.

School and college administrators, including superintendents and principals, often first work as teachers. Administrators for elementary and secondary public schools handle finances, record keeping, course development, hiring, enforcement of state requirements, union negotiations, maintenance of school properties, and other management duties. At the college level, administrators act as presidents, vice presidents, deans, admissions officers, financial aid managers, student advisers, buildings and grounds managers, and department heads.

More public schools are hiring teacher assistants rather than new teachers when there is a temporary swell in the number of students. Teacher assistants do not have to be certified teachers, but in many states they must have an associate's or other two-year degree. They do not teach, but help with record keeping, discipline, planning, and organizing in the classroom.

Association leaders and educators in government offices also often begin their careers as teachers. To be qualified and experienced for these higher level positions, most education administrators and government officials have completed graduate study in education.