Atomic metal catalysis (AMC) provides an effective way to enhance activity for the oxygen reduction reaction (ORR). Cobalt anchored on nitrogen‐doped carbon materials have been extensively reported. The carbon‐hosted Co‐N4 structure was widely considered as the active site; however, it is very rare to investigate the activity of Co partially coordinated with N, for example, Co‐N4−xCx. Herein, the activity of Co‐N4−xCx with tunable coordination environment is investigated as the active sites for ORR catalysis. The defect (di‐vacancies) on carbon is essential for the formation of Co‐N4−xCx. N species play two important roles in promoting the intrinsic activity of atomic metal catalyst: N coordinated with Co to manipulate the reactivity by modification of electronic distribution and N helped to trap more Co to increase the number of active sites.