Contractors are responsible for the construction of projects on a contractual basis on behalf of their clients. In the construction industry, contractors are hired directly by builders or third-party employers in order to offer independent professional services. Most of the time, these services are given to the hiring firm as part of a contract that they enter into with them. Further, the services are being provided as part of an agreement under which specific services are to be provided for a set period of time as part of the agreement.

The role of a construction contractor is to provide workers with the skills they need to safely perform and complete specialized tasks. There may be times when a hiring firm needs to hire contractors in order to make up for a lack of expertise or manpower on their part.

An instrumental figure in a complex construction project is the general contractor. In this role, the contractor hires any necessary subcontractors and coordinates their services. Prime contractors, main contractors, and principal contractors are also known as general contractors.

When compared to most other industries, construction has a higher incidence of injuries and fatalities. Employers are so concerned about safety that contractors often highlight their safety record. Contractors can complicate employment relationships. The jobsite can host the builder's employees, the contractors the builder has hired, and the subcontractors those contractors have hired. In safety incidents involving contractors, joint parties are generally responsible and liable. Contractors and hiring firms share responsibility when construction projects are involved. General contractors and subcontractors are responsible for incidents involving subcontractors. 

Employing construction contractors can be both beneficial and risky when it comes to workplace safety. As one of the benefits of hiring competent contractors is that well-trained workers can perform the work safely and may be more likely to finish it on time. Contractors, on the other hand, bring people to a job site who are not directly under the builder's control. Although employers should do their due diligence when hiring contractors, the general contractor is ultimately responsible for selecting subcontractors.

General contractors can be held liable for safety risks as long as their due diligence is sufficient.

Work outlined in the contract and work delegated to subcontractors is the prime contractor's responsibility. The work they oversee is also subject to their liability. After a client hires their firm, subcontractors retain some responsibility for their own workers' safety.

While both employers and contractors may be fined, charged, and sued for injuries and deaths caused by unsafe practices, violations tend to target employers and general contractors. Safety legislation must be followed by all on-site workers.

A lot of this is similar to that of a construction manager, but in this role, the trade contracts (or works contracts) are placed with the management contractor rather than the client, as is the case with a construction manager.

Clients enter into a long-term multi-project relationship with contractors that includes the introduction of competition at the subcontract level as a consequence of the long-term relationship. An individual who has completed a prime contract, however, is usually only appropriate for very large clients like the Ministry of Defence. This is because the ministry continually commissions construction buildings as well as refurbishment projects for its facilities.

Usually, this method is preferred by the government and includes the appointment of a full project team (including contractors, suppliers, designers, and sometimes facilities managers) to design and construct the works as part of the project.

A contractor is appointed not only to design and build the works, but also to manage them during operation. Sometimes, the contractor will provide operational services in addition to building maintenance, such as the provision of prison staff or the sterilisation of hospital instruments.

The contractor may also be designated as the principal contractor under CDM regulations. This is in order to plan, manage and coordinate health and safety requirements during the construction process.