Definition
The person who has the final call on the decision to purchase.
See The most important buying roles
The closer you are to talking with the Decision Maker, the more likely you are to close the sale.
You may not connect with a Decision Maker from the get-go and in certain cases you will not connect to them at all. In such cases, you rely on Champions, Influencers, and other roles to progress the opportunity. Even in such cases, however, a Decision Maker will be involved in the purchase.