Abstract We examined whether the diversity of daily activities (“activity diversity”) is associated with the diversity of daily emotions (“emodiversity”) and if the association differs by age. Two samples of adults from the Midlife in the United States Study provided activity and emotion data for eight days. Greater activity diversity was associated with greater positive and negative emodiversity in each sample. Age moderated the association between activity diversity and positive emodiversity in an older sample, such that association was stronger for younger adults than for older adults. Results from data combining the two samples revealed that the associations of activity diversity with positive or negative emodiversity were significant when age < 70, 71 years, respectively. Broad and even participation of daily activities may provide more opportunities to experience rich and balanced emotions in adulthood. The weaker associations in older age may suggest the need to promote active lifestyles in later life.