Proactive self-management is likely to be part of resource maintenance and well-being in later life, but empirical evidence is scarce. Therefore, we investigated (a) whether self-management ability (SMA) is associated with lower resource deficits, and (b) whether it is related directly and indirectly to life satisfaction (LS), positive affect (PA) and negative affect (NA). Regression and mediational analyses (N = 439, aged 65 years and older), showed that SMA related to resource deficits, and had direct associations with the three well-being indicators. Indirect associations—via lower resource deficits—were found for LS, whereas the association between SMA and PA was mostly a direct one, being mediated only to a small extent by physical resource deficits. The association between SMA and NA was mediated only by social resource deficits. It is concluded that better SMA seems to matter to resource maintenance and well-being, but future research needs to unravel the differential findings for physical and social resource deficits and for the separate well-being indicators.