Almost every time I give a keynote on innovation, I am asked by a new professional (or two, or three..) about how they can go about driving change in their organization from the "bottom of the totem pole." The secret to accomplishing leadership from an entry or mid-level position can often be found in the "unwanted" tasks.
It is a choice to embrace an altered state, i.e. a transformation. Once you are successful with a transformation, your organization is equipped to replicate the success. Transformation provides a built-in learning opportunity for everyone in your organization, which makes the organization nimble and eager to take on new things.
For the organization at large, it is the chief executive who owns the culture. The larger the organization, the more cultures multiply. From department to department, cultures can be quite different, depending on the department leader. In any case, the leader of the organization ultimately owns the organizational culture.