at the helm
In charge, in command, as in With Charles at the helm, the company is bound to prosper. This phrase transfers the idea of steering a ship to directing other enterprises. [Early 1500s] Also see the synonym at the wheel.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.