It has been recorded from lowland forest as well as in montane forests and bamboo zones. Kingdon (1997) suggested that the presence of remains of rodents of the genera Dasymus and Otomys in stomachs suggests that it  hunts frequently in the thick herbaceous growth around swamps.

This species is known only from central and southern Kenya, southeastern Uganda, and from the Udzungwa Mtns (900 km to the south) in Tanzania (Van Rompaey and Kingdon 2013). The Tanzanian population seems to be highly localised: camera-trapping conducted from 2002 to 2004 at 76 sites throughout the Udzungwa Mountains recorded Jackson’s Mongoose in only five sites in an area of only few km² within Matundu Forest (De Luca and Rovero 2006). Intriguingly, however, extensive camera-trapping in this forest in 2013–2014 did not reveal the presence of this species again (F. Rovero and R. Havmøller unpublished data). It has been recorded from about 300 m asl to montane elevations in the Aberdare Mtns, Mt Kenya and Mt Elgon up to 3,300 m asl.

In Kenya, Jackson’s Mongoose is confirmed in the Aberdare N. P. and Mt Kenya N. P., and is also likely to occur in Mt Elgon N. P. (Van Rompaey and Kingdon 2013). In Tanzania, all confirmed localities lie within protected areas, including the Udzungwa Mountains N. P. De Luca and Rovero (2006) recommend full protection of forests adjacent to the Udzungwa Mountains N. P., and that other East African lowland forests (including those near Matundu and Nambiga Forest Reserves) be surveyed for the presence of Jackson’s Mongoose.