Every employee affects the direction of the company in some amount, commensurate with their hierarchical level, security clearance, expertise, etc.

In normal, day to day operations, the CEO tends to have a bigger share of influence than other employees, but he neither has sole influence, nor always the biggest influence.

One could very well argue that Jonathan Ives had a bigger influence than Steve Jobs on Apple's direction around the time of iPod's release, for example. That product singlehandedly changed Apple's market segment and consumer perception.

In short, a CEO is just an employee, often getting paid more than the average employee, and often having more influence than the average employee, but not always.