Functional leadership model

Functional leadership theory (Hackman & Walton, 1986; McGrath, 1962) is a theory for addressing specific leader behaviors expected to contribute to organizational or unit effectiveness. This theory argues that the leader's main job is to see that whatever is necessary to group needs is taken care of; thus, a leader can be said to have done their job well when contributing to group effectiveness and cohesion.

Source: Wikipedia — Functional leadership model (CC BY-SA 4.0)