The recent requirement for superwettable materials for efficient absorption of heavy oils and waste organic solvents has led to the advancement of various functional materials, where the disposal and non-degradation of their constituents in the environment is a threat, contributing to global warming. In the present work, we report an in situ fabricated, heterogeneous wettable, and biodegradable PLA Janus fabric based on a cellulosic-substrate, functionalized with surface-modified nanoclay. The developed Janus fabric, which is fabricated via an efficacious electrospinning technique, possesses superhydrophobicity (WCA ∼ 152°)/superoleophilicity (OCA ∼ 0°) and low ice-adhesion, owing to its hierarchical textured morphology, as revealed by FE-SEM analysis, along with an excellent oil–water separation efficiency of 99.16%, which is maintained for 30 reusable washing cycles, and a maximum permeation flux of around 65 000 l m⁻² h⁻¹ for n-hexane from a solvent–water mixture. More importantly, the reported Janus fabric demonstrates microbial and hydrolytic biodegradation with 78% weight loss in 28 days, at a rate of 2.79 ± 0.5% per day at room temperature, under an in-house developed biotic system constituted of decompost slurry. The FESEM analysis of the biodegraded samples revealed the presence of Gram-positive Bacillus polymyxa bacteria. Moreover, the engineered Janus fabric retains its inherent properties under various acidic and basic conditions (pH = 1 to 10), hyper-saline solutions (10% to 30%), mild-detergent solution, UV-radiation (254 nm), and sub-zero temperatures (−20 °C to 0 °C). The successive results demonstrate that the developed Janus fabric can be effectively used as a proficient biodegradable material for the efficient absorption of heavy oils/waste organic solvents in comparison with non-degradable synthetic materials.