Field experiments were conducted to determine the mobility, distribution and naturally occurring glutathione (GSH)-based phytoaccumulation of cadmium and zinc in the sewage-irrigated alluvial soils, Allahabad, India. Frequent sewage-irrigation (up to 100 mL kg−1 soil) at 5 days’ interval indicated enrichment of soil profiles with Cd and Zn more prominently in surface soils and sub-surface soils below to the depth of 0.6 m and augmented cadmium and zinc accumulation in shoot tissues of Brassica species up to 10.6 and 31.5 mg kg−1, respectively. Both cadmium and zinc were found significantly correlated with organic matter and cation exchange capacity of the soils indicating their dominant role in the sewage-irrigated soils. Raphanus sativus L. and Brassica napus L. accumulated significant quantity of cadmium and zinc, and higher concentration of GSH in their shoot tissues synergistically boosted translocation as well as accumulation of metals in plants, especially at plant maturity. However, cadmium showed higher translocation than zinc. Such evidence supports the conclusion that elevated natural GSH concentrations of Brassica species during their developed stage of plant growth are involved in metal hyperaccumulation, which ensure their potential for phytoremediation of cadmium and zinc in the sewage-irrigated soils. Thus, the use of the unused part (mostly leaves) of these species as an innovative technology for phytoremediation is suggested.