Someone to whom clear responsibility has been assigned for the success of a value stream. The value stream can be defined at the product or company level (including product development) or at the plant or operational level (from raw material to delivery). 

The value stream manager is the architect of the value stream; he identifies value as defined from the customer's perspective and leads the effort to achieve an ever-shorter value-creating flow. 

The value stream manager ensures that the organization focuses on aligning activities and resources with value creation, even if none of the resources (money, assets, people) actually "belong" to the value stream manager. Thus, value stream management involves a distinction between responsibility, which lies with the value stream manager, and control, which lies with the functions and departments that control the resources. The functions must provide the resources needed to realize the vision of the value stream as defined by the value stream manager. The value stream manager leads based on influence, not hierarchical position, and thus can be as effective in a traditional functional organization as in a matrix organization. The latter avoids a common flaw in matrix organizations: the lack of clear responsibilities, authority and effective decision-making. 

The archetype of the role of the value stream manager is Toyota's chief engineer, who has only a minimum of staff and resources under him. 

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