Temperament and physical activity (PA) have been examined in children and adolescents, but little is known about these associations in adulthood. Personality traits, however, are known to contribute to PA in adults. This study, which examined both temperament and personality characteristics at age 42 in relation to frequency of PA at age 50 (JYLS, n = 214-261), also found associations with temperament traits. Positive associations were found between Orienting sensitivity and overall PA and between Extraversion and vigorous PA among women and between low Negative affectivity and overall and vigorous PA among men. Furthermore, Orienting sensitivity and Agreeableness were associated with vigorous PA among men. Temperament and personality characteristics also showed gender-specific associations with rambling in nature and watching sports.