This article reviews the role of active hydrogen (H*) in electrochemical ammonia synthesis (EAS) and discusses strategies for its regulation to enhance EAS performance. EAS offers advantages over the Haber–Bosch process, including lower energy consumption and reduced carbon emissions. However, the competing hydrogen evolution reaction (HER) limits the yield, selectivity, and current efficiency of ammonia production. H* is a critical intermediate in both EAS and HER, and its regulation is essential for improving EAS performance. The article provides a comprehensive overview of H* generation, conversion, identification, and quantification in electrochemical reactions. It also summarizes the role and control strategies of H* in EAS, focusing on regulating H* generation and consumption to enhance the activity, selectivity, and Faradaic efficiency (FE) of ammonia production. The review highlights the challenges and perspectives in H* regulation, emphasizing the need for accurate detection methods, understanding of H* reaction mechanisms, and rational catalyst design. The article also discusses various strategies for H* regulation, including inhibiting the Volmer and Heyrovsky/Tafel steps, generating H* on demand, and promoting its generation and consumption. These strategies are applicable to different EAS reactions, such as NRR, NO3− RR, and NORR. The review concludes that further research is needed to overcome the challenges of H* regulation and improve the efficiency and selectivity of EAS. The article emphasizes the importance of developing advanced detection methods, understanding H* reaction mechanisms, and designing efficient electrochemical cells to advance EAS technology.This article reviews the role of active hydrogen (H*) in electrochemical ammonia synthesis (EAS) and discusses strategies for its regulation to enhance EAS performance. EAS offers advantages over the Haber–Bosch process, including lower energy consumption and reduced carbon emissions. However, the competing hydrogen evolution reaction (HER) limits the yield, selectivity, and current efficiency of ammonia production. H* is a critical intermediate in both EAS and HER, and its regulation is essential for improving EAS performance. The article provides a comprehensive overview of H* generation, conversion, identification, and quantification in electrochemical reactions. It also summarizes the role and control strategies of H* in EAS, focusing on regulating H* generation and consumption to enhance the activity, selectivity, and Faradaic efficiency (FE) of ammonia production. The review highlights the challenges and perspectives in H* regulation, emphasizing the need for accurate detection methods, understanding of H* reaction mechanisms, and rational catalyst design. The article also discusses various strategies for H* regulation, including inhibiting the Volmer and Heyrovsky/Tafel steps, generating H* on demand, and promoting its generation and consumption. These strategies are applicable to different EAS reactions, such as NRR, NO3− RR, and NORR. The review concludes that further research is needed to overcome the challenges of H* regulation and improve the efficiency and selectivity of EAS. The article emphasizes the importance of developing advanced detection methods, understanding H* reaction mechanisms, and designing efficient electrochemical cells to advance EAS technology.