Cladosporium sphaerospermum consists of a complex of poorly morphologically differentiated, "cryptic" species that share many physiological and ecological attributes.

[3] Cladosporium sphaerospermum also produces ramoconidia 6–14 × 3.5–4.0 μm in length[3] and this feature can be used as a method of distinguishing between similar species.

[5] This fungus is xerotolerant as it can thrive in environments with low water activity caused by high salinity (halotolerant) or other dissolved solutes.

[9] This trait may have arisen because these fungi and many others from the genus Cladosporium are secondary colonizers and frequently dwell in environments poor in nutrients.

[5] Cladosporium sphaerospermum is able to enhance polycyclic aromatic hydrocarbon biodegradation in soils due to reactive oxygen species produced as secondary metabolites, such as H2O2.

[10] This species is a prolific producer of the pigmented secondary metabolite, melanin, thought to serve as a protective mechanism against UV irradiation, enzymatic lysis, oxidant attack, and fungal infections from other competing fungi.

[11] Cladosporium sphaerospermum is a cosmopolitan fungus that inhabits city buildings and the environment and because of its airborne nature it can move rapidly between locations, though the extent of this is lacking in research.

[16] There has been one reported case in which a female patient developed swelling on the dorsum of her hand which, after testing with Grocott's methenamine silver stain and lactophenol cotton blue, confirmed the presence of dematiaceous hyphae compatible with C.

[11] In 2020 the U.S. Department of Agriculture announced it had found evidence that a certain strain of the fungus has a positive effect on plant growth.

During the 30 day study the amount of radiation reduction beneath a 1.7 mm thick layer of fungus at full maturity was measured to be 2.17±0.35%.

Estimates of a 21 cm thick layer of the fungus indicate it could attenuate the annual dose from the radiation on the surface of Mars.