Refers to a person who holds a leadership position or is recognized as the central figure in a group, team, or organization. Often implies a natural or acknowledged status rather than just a formal title.
He leads everyone as the team's leading figure.
This group lacks a leader figure.
Compound of リーダー (leader) and 格 (status/rank). The suffix 格 indicates a recognized standing or role, so リーダー格 literally means 'leader status' or 'person of leader rank'.