In this research, we designed a durable quasi-liquid surface (QLS) by tethering flexible polymer on various solid substrates such as silicon, glass, and aluminum. The quasi-liquid surface is made by tethering one end of the flexible polymer of polydimethylsiloxane on a solid substrate but keeping the other end mobile. Simultaneous hydrolysis and polycondensation occur in this one-step surface grafting without any solvent, catalyst, or harsh conditions. The untethered end of the polymer has mobile chains that behave like a liquid layer and greatly reduce the interfacial adhesion between the surface and foreign liquids/solids. Such a quasi-liquid surface with a 30.1 nm flexible polymer layer shows ultralow contact angle hysteresis (≤1.0°) to liquids regardless of their surface tensions. We engineered QLS by tethering flexible polymers with gradient grafting density to form gradient QLS, which achieved spontaneous droplet movement. We further used the liquid phase fabrication method to form QLS, which was scalable and can be used for small- and large-scale ice removal alike. We have demonstrated that the quasi-liquid surface shows robust performances in repelling highly wetting liquids, harvesting water, and removing ice, respectively. The highly wetting perfluorinated liquids like FC72 and Krytox101, as well as complex fluids like urine and crude oil, can be repelled from the surface. The QLS was able to survive and maintain its robust performance for liquid repellency and ice removal. Meanwhile, the vapor-phase QLS shows a stable dropwise condensation with high heat-transfer performance for a prolonged period of 39 h under day-and-night steam condensation.