I'm unable to remember a single-word substitute for "a person who takes happiness as his/her goal of life"
Eudaemonism the ethical doctrine that personal happiness is the chief good and the proper aim of action
I'm not sure there is a single word for this concept, although epicure is one devoted to sensual pleasure (in its older sense). Further along that wavelength is the word libertine.
voluptuary: a life devoted to the pursuit of enjoyment of luxury and pleasure;