The role of folivorous primates in ecosystem restoration has been largely overlooked. This may primarily be due to the lack of basic ecological information on many of these species. The northern sportive lemur (Lepilemur septentrionalis), for example, is one of the most endangered primates in the world, yet we lack baseline ecological knowledge of this lemur. This dearth only serves to exacerbate their situation as conservation initiatives do not have the fundamental information needed to properly manage conservation efforts for this species. To obtain an ecological baseline for L. septentrionalis, we used instantaneous focal animal sampling to collect behavioral data, including strata use, to investigate feeding ecology for five individuals over a 12-month period (December 2018-November 2019) in Montagne des Français. We conducted a total of 755.1 hours of observation. Our results showed that L. septentrionalis’ diet consisted of mature and young leaves, ripe and unripe fruits, flowers, and buds. Mature leaves of Tamarindus indica were the most frequently consumed resource, yet L. septentrionalis consumed 61 different species of plants from 23 families. Though mature leaves were the most frequently consumed resource overall, we only observed L. septentrionalis eating them during the cold/dry season. The most frequently used stratum during feeding was the canopy, which correlated strongly with the consumption of mature and young leaves. Though many aspects of this species’ diet are similar to other Lepilemur, there are specific ecological conditions, notably seasonal frugivory, which should be considered when developing restoration ecology programs in Montagne des Français.