This research examines the mediating roles of green supply chain management practices, namely, green purchasing practices (GPP), green manufacturing practices (GMAP), green distribution/ packaging practices (GDPP), and green marketing practices (GMP) between two components of effective leadership practices: leading organizational practice (LOP) and leading staff practice (LSP) and business competitiveness (BC).Design/methodology/approach -The research applied a quantitative approach, and a survey instrument was designed to collect empirical data from the Cihan group in Iraq. The data were analyzed by using partial least squares -structural equation modeling (PLS-SEM).Findings -The results showed that LOP is significantly related to the green practices: GPP, GMAP, GDPP, and GMP. The research showed that LSP is positively associated with green supply chain practices: GPP, GMAP, GDPP, and GMP. The results also revealed the direct relationship between the same practices: GPP, GMAP, GDPP, and GMP with BC. The results showed that there was no significant correlation between LOP and BC. Meanwhile, LSP was positively and significantly related to BC.Discussion -The research's findings revealed that all four practices of GSCM as GPP, GMAP, GDPP, and GMP, fully mediated the impact of LOP on BC since there was no significant direct relationship between LOP and BC. The research showed that green practices in the form of GPP, GMAP, GDPP, and GMP partially mediated the impact of LSP on BC, as the results showed a significant direct relationship between LSP and BC.