The non-heme Fe(II)/2OG-dependent halogenases have garnered significant attention as candidates for biocatalyst design due to their chemical prowess for halide insertion into sp3 C-H bonds. Synthetic and natural halogenated products play important roles in agriculture, industrial processes, and pharmaceutical applications. The bulk of mechanistic evidence for these enzymes has been limited to enzyme systems that require substrates tethered to carrier proteins. However, recently discovered enzymes have been identified to target freestanding substrates that retain the active site environment for Fe(II)/2OG incorporation. In this work, we explore the mechanistic paradigm for the halogenase, AdeV, which is responsible for the O2-dependent conversion of the nucleotide 2’-deoxyadenosine monophosphate to 2’-chloro-2’-deoxyadenosine monophosphate. Through a multifaceted approach of organic synthesis, transient-state kinetics, Mössbauer spectroscopy, and analysis of reaction product assays the following mechanistic insights were detailed: (1) the rapid addition of O2 generates a long-lived intermediate species that correlates to the chloroferryl intermediate that is comparable to other Fe(II)/2OG-dependent halogenases; (2) freeze-quench Mössbauer analysis revealed two discrete Fe(IV)-oxo species that appear sequentially and undergo “interconversion” during the catalytic process; (3) analysis of AdeV catalysis shows product accumulation during transition between the chloroferryl intermediates that suggests an equilibrium between intermediates. In summary, these experimental results imply that the AdeV catalytic cycle proceeds through a nuanced pathway distinguishable from other Fe(II)/2OG halogenases.