It was discovered by Danish marine ecologist Tom Fenchel and named by him and taxonomist David J. Patterson in 1988.

[2] Cafeteria roenbergensis reproduces asexually via binary fission[citation needed], first replicating the flagella and internal organelles before the cell divides.

Cafeteria roenbergensis is a suspension feeder, meaning that it feeds by filtering suspended bacteria, its primary food source, and other particulate matter from the water.

Bacterivorous nanoflagellates, the general group to which C. roenbergensis belongs, make up a significant portion of the oceans' protozoan communities, as well as those in freshwater, soils and other habitats.

[7] Ishigaki and Sleigh (2001) found that C. roenbergensis ceased to reproduce when the concentration of bacteria that they were grazing on became less than 2.0×107 cells ml−1.

[9] The impact of CroV on natural populations of C. roenbergensis remains unknown; however, the virus has been found to be very host specific, and does not infect other closely related organisms.

It has one other known species in its genus, Cafeteria minuta, which was found living in tropical marine sediments by Larsen and Patterson in 1990.

[5] Marine biologist Tom Fenchel, one of the two species authorities who first described C. roenbergensis, is credited with having joked about the chromalveolate's name: "We found a new species of ciliate during a marine field course in Rønbjerg and named it Cafeteria roenbergensis because of its voracious and indiscriminate appetite after many dinner discussions in the local cafeteria.

[13] The mitochondrial translation code in C. roenbergensis is not standard in comparison to its closest known relatives, Phytophthora infestans and Ochromonas danica.