The view that happiness consists in virtuous action is an attractive view. A relationship to happiness may help explain, define and give distinctively human content to the virtues, and may encourage us to cultivate virtue. Yet many virtue theorists today are wary of this view. There is tension between ordinary notions of happiness and virtue. There is also concern that choosing virtue for the sake of happiness is inappropriate. However, I defend a version of the claim that happiness consists in virtuous action, and I show that when properly understood, happiness is an appropriate motive for virtuous action. Key to my view is an account of friendship whereby actions and the happiness they constitute are routinely shared. I analyze four competing views of the relationship between virtue and happiness. John McDowell holds that happiness consists in virtuous action, performed for its own sake, and hence is independent of goods of fortune, but this view is unrealistic and encourages self-absorption. Rosalind Hursthouse maintains that the virtues are conducive to happiness, but neither necessary nor sufficient: happiness consists in goods of fortune. I argue that tensions in Hursthouse's text are better resolved by the bicameral view: happiness consists in virtuous action, but one's ability to act depends on goods of fortune. Richard Kraut's reading of Aristotle yields a bicameral view centered on contemplation, but this is overly narrow. The perfectionist view, including ethically virtuous action in happiness, mitigates the self-absorption of McDowell's view at the cost of introducing unsavory competition for opportunities to act. The four preceding views construe happiness individualistically. However, the best human actions can only be performed in cooperation. Actions are shared through cooperation and, more importantly, shared choice. Since happiness consists in actions, happiness too is often shared. Shared action overcomes the self-absorption of McDowell's view and the competition of the perfectionist view. In helping another to act well, one participates in her action, rendering her action constitutive of one's own happiness as well as hers. Where one finds happiness precisely in the happiness of another, one's happiness is an appropriate motive to virtue.