This chapter investigates how sustainability roles are distributed within banks and how this division of labor affects the overall implementation of sustainability strategies. Drawing on interviews with professionals from four Icelandic banks, this study examines the interplay between sustainability specialists, committees, and operational managers. It also examines the professional backgrounds, authority, and visibility of sustainability roles and how these factors impact the credibility and influence of sustainability initiatives. The chapter argues that successful sustainability implementation depends on clearly defined responsibilities, cross-functional cooperation, and an ongoing shift toward embedding sustainability across all units. The structure of sustainability work within banks goes far beyond formal titles and committee charts. It is deeply embedded in daily practices, interpersonal relationships, and institutional routines that sustain or hinder meaningful progress. In Icelandic banks, the division of labor for sustainability was highly variable, often relying on a small number of professionals tasked with ambitious mandates and limited support.