All District government employees under the personnel authority of the Mayor belong to one of five services: Career Service, Excepted Service, Executive Service, Legal Service and Management Supervisory Service.

Career Service

Career Service appointees are selected from the most qualified applicants, based on specific job requirements, with special consideration to veterans and DC residents (although District residency is not required). Upon completion of a probationary period, employees have job protection and due process rights and can be removed only for cause or as a result of a reduction-in-force. Most of the District's workforce is in the Career Service, which includes professional, administrative, technical and clerical workers, wage grade employees and uniformed employees of the police and fire departments.

• Term Position
  A term appointment can last from 13 months to four years, and cannot exceed the termination date. Term positions can be filled up to a DS-12 level through the non-competitive hiring process.
• Temporary Position
  A temporary appointment can last up to 12 months. Temporary positions can be filled up to a DS-12 level through the non-competitive hiring process. Employees in temporary positions receive no benefits.

Excepted Service

There are several categories of employees within the Excepted Service. The majority of these are employees on the personal staff of the Mayor and employees serving in policy positions. Excepted Service positions are filled non-competitively. Excepted Service employees are required to live in the District, and have 180 days from the date of appointment to establish residency. They are required to provide proof of residency.

Also, included in the Excepted Service are the following:

• Statutory positions, which are established by law
• Public employment positions, which are created under public employment programs established by law
• Special employment program positions, which are established to provide training or job opportunities for rehabilitation purposes or for disadvantaged people
• Federal grant-funded program positions, which have a limited definite duration
• Positions established under cooperative educational and study programs
• Professional, scientific, or technical expert or consultant positions.

Executive Service

The Executive Service consists of heads of agencies subordinate to the Mayor. It was established to ensure that the executive management of the District of Columbia government would be responsive to the needs of the citizens and the goals of the government. The Mayor nominates people to serve as agency heads, subject to confirmation by the Council.

The majority of Executive Service employees serve at the pleasure of the Mayor and are subject to residency requirements, unless otherwise provided by law or Council resolution. Executives are required to live in the District, and have 180 days from the date of appointment to establish residency. They are required to provide proof of residency.

Legal Service

Legal Service employees who direct the organizational work of other attorneys, such as Deputy Attorney Generals and General Counsels, are part of the Senior Executive Attorney Service, which is part of the larger Legal Service. Senior Executive Attorneys are accountable and responsible for the effectiveness and productivity of the Legal Service. These attorneys serve at the pleasure of the appointing authority. Only residents of the District of Columbia are eligible to service in the Senior Executive Attorney Service.

Management Supervisory Service

Management Supervisory Service (MSS) appointees are selected from the most qualified applicants, based on specific job requirements, with special consideration to veterans and DC residents (although District residency is not required). Employees in the MSS serve at-will. Those appointed to the MSS enjoy the benefits of a separate, more competitive pay structure and are offered a targeted training curriculum with courses on performance management and evaluation, human resources systems and leadership development.

MSS employees with Career Service or Educational Service status may retreat, at the discretion of the personnel authority, within three months of termination, to a non-MSS position within their agency.