It is an erect to spreading shrub with narrowly egg-shaped to almost linear leaves, and toothbrush-like groups of pinkish-fawn flowers with a pink to red style.

[2][3][4][5][6][7] Grevillea longifolia was first formally described in 1830 by Robert Brown in his Supplementum primum Prodromi florae Novae Hollandiae, from specimens collected by George Caley near Port Jackson in July 1807.

It grows in shaded or part-shaded situations in woodland or forest, under such trees as blue leaved stringybark (Eucalyptus agglomerata), Sydney peppermint (E. piperita), stringybark (E. oblonga), smooth-barked apple (Angophora costata) and red bloodwood (Corymbia gummifera), and shrubs such as gymea lily (Doryanthes excelsa), and near creeks with such shrubs as Lomatia myricoides, watergum Tristania neriifolia, kanooka (Tristaniopsis laurina) and trees blackbutt (Eucalyptus pilularis) and coachwood (Ceratopetalum apetalum).

The seed are sometimes eaten by insects, or by native mammals such as the bush rat (Rattus fuscipes) and swamp wallaby (Wallabia bicolor).

[5] Grevillea longifolia adapts readily to cultivation, and can be propagated vegetatively by cutting as plants have a tendency to hybridise, making seed parentage unclear.