As a project leader, your primary task is to manage people. "Satisfy stakeholders!" is the project manager's mantra. For successful projects, it's not enough to deliver on the customer's demand; projects have to meet all stakeholder expectations.

Identifying stakeholders is a primary task because all the important decisions during the initiation, planning and execution stages of the project are made by these stakeholders.  

Stakeholders in Project Management

Project leader (or project manager) – the head of the project; defines, plans, controls, and leads the project  >>>

Project team members – produce the outputs (deliverables) for the project; participate in the project management process; contribute their skills and effort to perform tasks  >>>

Sponsor (or upper manager) – the person with formal authority who is ultimately responsible for the project; oversees the project; acts as a liaison between the upper management team and the project leader; provides authority, guidance, and maintains project priority

Project customer – the person or group whose needs and requirements drive the project; receives the final output(s) that the project produces; provides product requirements and funding

Functional managers (also known as resource managers or line managers) – provide company policy an resources, particularly people who are involved in the project