In his 1956 book Das Gemüt, Stephan Strasser presents an original phenomenological investigation into human happiness and pleasure. We will examine Strasser’s theory of happiness in more detail and reveal how he incorporates important phenomenological insights from Thomas Aquinas’ theory of the passions of the soul. Both Strasser and Aquinas view happiness as the fulfilment of intentional striving and differentiate between various feelings associated with the pursuit and attainment of a goal, such as joy and pleasure. However, while Aquinas believes that only an imperfect form of happiness can be attained in this life, Strasser aims to determine the essence of the highest form of happiness possible for human beings as the felt anticipation of perfect happiness in the future. Strasser, therefore, interprets Aquinas’ theory through the lens of an existential-phenomenological approach.