How does being a knower and possessing knowledge contribute to living well? Some have assumed that the eudaimonic value of knowledge is exhausted by its role as either a means or a final end. On this basis, it has been concluded that knowledge is not always valuable since its value will depend upon the ends that one has. I propose to expand our exploration by considering how knowledge might be valuable in virtue of being constitutive of certain eudaimonic goods. Using achievement as an example of an eudaimonic good, I argue, by way of considering its relations to credit and luck, that knowledge is necessary for achievement.