Fulfillment, sometimes called eudaimonic happiness, or subjective well-being is primarily an emotion, secondarily a thought, and it reaches into the domain of action. It is distinguished from happiness in that it reaches into these other domains besides emotion. On these grounds, we could say that it is a global desire.

As usually described, fulfillment is also more enduring than happiness, which can be fleeting. Fulfillment is best seen as a quality of being that is related to a sense of long-term purpose, or purpose over a lifetime. Therefore, the positive association between prosocial behaviors, and also eudaimonic motives, and eudaimonic happiness should come as no surprise. Work performance appears to improve more in response to eudaimonic than hedonic happiness. Eudaimonic motives seem to improve performance among college students. A posited relationship between eudaimonic happiness and entrepreneurship is being investigated.

Fulfillment also reaches outside but does not neglect the self. Satisfaction, pleasure and longevity apply to the individual. Mainly, happiness does too. Fulfillment goes beyond that. A bank robber might experience happiness with his stolen wealth but most of us would strongly question whether his life in fulfilled. Many people say that parenthood fulfills them. Others say that they are fulfilled by serving others: for example, by teaching, providing for others or defending their country. As social creatures, we humans thrive on our relationships with others; the well-being of those we care about makes us happy. People who are childless or who live in solitude may find fulfillment too but our relationships with others add a dimension to our preferences and desires that most people identify as creating the distinction we call fulfillment. In this too, fulfillment is distinguished from mere happiness. It also begins to open us to spirituality.

Subjective well-being (SWB) has been mapped via brain fMRI. Subcortical brain volume appears to play a role in SWB.

The effects of SWB appear to be essentially universal around the world. Predictors include economic development, environmental health, equality and freedom. People who report higher levels of subjective well-being tend to live longer and happier lives. However, cultural values can play a role in the elderly.