Landfill mining (LFM) of decade-old landfills and legacy waste dumpsites has indicated that about half of the excavated waste is primarily comprised of a mixture of decomposed organic matter, soil, sand, and other miscellaneous fine particles that are popularly known as landfill-mined-fine-fractions (LFMFF). Several field and laboratory investigations performed to determine the efficacy of reusing LFMFF revealed that heavy metals (HMs) leaching is the primary concern that restrained its potential utilization. Among the various parameters that can affect the leaching behavior of HMs, pH is the most significant one. The current study analyzes the leaching characteristics of four HMs (Cu, Cr, Zn, and Fe) from LFMFF by performing pH-dependent leaching test. The liquid–solid partitioning (LSP) curves of Cu and Cr revealed the amphoteric leaching behavior, demonstrating the elevated release at higher acidic and alkaline pH conditions, with minimal release at neutral pH levels. On the contrary, the LSP curves of Zn and Fe exhibit cationic leaching behavior where the released concentrations dropped monotonically as the pH level increased. The release of any particular HM is governed by the dissolution and precipitation of its oxide, (hydr)oxide, and carbonate compounds. The released concentrations of Cu and Zn were below the USEPA stipulated maximum contamination limits (MCL) within the permitted pH range of drinking water (6.5–9), but Cr and Fe concentrations frequently exceeded the MCL at every pH level. The study provides a comprehensive assessment of the release behavior of HMs from LFMFF under diverse environmental conditions.