The IUCN Red List conservation status is rated as Least Concern, as the line-cheeked spinetail is common along its range and is presumably stable.

[2] The line-cheeked spinetail was formally described in 1859 by the English zoologist Philip Sclater from a specimen collected near the town of Cuenca in Ecuador.

[2] The majority of species within the genus Cranioleuca diverged relatively recently in a rapid speciation event beginning approximately 3.5 Ma.

One hypothesis is that a rapid change in plumage, in conjunction with some other traits, may have caused reproductive isolation and speciation.

[6] There is evidence that climatic niches have been a driver of speciation within the genus, particularly within the line-cheeked spinetail species complex.

[2] It has a rufous crown; with a well-defined white supercilium; a pale throat; and some streaking on its ear coverts.

[7] The line-cheeked spinetail is a diurnal species and vocalizes most actively at dawn and dusk to maintain their breeding territory boundaries.

[7] Both adults and juveniles respond strongly to playback of songs, suggesting aggression between individuals within the species.

A published observation of a breeding pair in Mashpi Protected Forest suggests that their distribution may extend further north in Ecuador than previously thought.

In Ecuador, line-cheeked spinetails can occupy elevations as low as 800m, whereas it is limited to 2000m is the more arid regions of its Peru range.

Line-cheeked spinetails occur primarily where there is dense evergreen vegetation, and are not found in deciduous and arid habitats.

The exterior was constructed out of moss, cucurbitaceous vine and covered in the hairy seeds of a Bombacaceae, while the interior was built with palm fibres, Lauraceae leaves and lines with epiphyte rootlets.