A project manager is one, who looks into the application of knowledge, skills, tools, and techniques to describe, organize, oversee and control the various project processes. Having said that, the roles and responsibilities of a project manager differ from company to company. It is important to understand what role a particular project manager will play in a certain company or organization.

The tasks to be handled by a project manager to successfully manage a project include:

- Integration Management- This is developing and managing the direction of the project

- Scope Management-This includes planning, defining and managing the scope of the project.

- Time And Cost Management-This covers developing a schedule, allocating resources and managing funds for the project.

- Quality Management-This involves taking care of the quality of the process in question such that it meets or even exceed various quality parameters set earlier.

- Human Resource Management- A manager needs to take care of his team, encourage and motivate them and make sure the team moves in the right direction.

- Communication Management- The manager needs to prepare a communication plan and make sure that there is a healthy communication, both horizontally and vertically.

- Risk Management- Various risks involved in a project should be identified and a mitigation and contingency plan needs to be developed to ensure that the project is not derailed at any point.

- Procurement Management- Various materials needed during the project needs to be procured and managed with the vendors and suppliers for successful completion of project.

A project manager is usually responsible for the success or the failure of the project. They first need to define the project and then build its work plan. If the scope of the project is not very clear, or the project is executing poorly, the manager is held accountable. However, this does not mean that the project manager does all the work by himself (which is practically impossible). There is an entire team under the project manager, which helps to achieve all the objectives of the project. However, if something goes wrong, the project manager is ultimately accountable.

Apart from this, depending on the size and the complexity of he project, a project manager may need to take on multiple roles. The project manager may need to assist with gathering business requirements, help to design a database management system or may prepare project documentation. A project manager may work full time on a large project, or may work part-time on various projects of smaller nature; or may alternatively handle various projects as well as handle other responsibilities like business analysis and business development.

At times, a project manager may have accountability but not authority. For example, he may be using certain resources but might not have direct control over those resources. At such times, the manager might find certain limitations over task execution, which might not take place as they might have liked. Not having direct control over the state of finances and finance allocation might cause ambiguity.
In order to be successful, the project manager must be given support by upper management and authority.