Powerbroker (noun)

A person who wields significant power and influence through control of political or economic resources or through connections with important people.

Origin:

20th century: from power + broker.

Examples:

1. He was a powerful powerbroker in the city's politics.
2. She was a powerbroker in the business world.
3. The powerbroker had a lot of influence in the city's politics.
4. The powerbroker was a behind the scenes player.
5. He was able to get things done because he was a powerbroker.