This dissertation explores what a new materialist line of thinking can offer the study of eighteenth-century Irish and British literature. It sees specific objects that were considered indicative of eighteenth-century Irish identity—coins, mantles, flax, and spinning wheels—as actively indexing and shaping the formal development of Irish character in fiction, from Jonathan Swift to Sydney Owenson. Through these objects, I trace and analyze the material origin stories of two eighteenth-century discursive phenomena: the developments of Irish national character and Irish literary character. First, in the wake of colonial domination, the unique features and uses of objects like coins bearing the Hibernian typeface, mantles, and flax helped formulate a new imperial definition of Irish national character as subdued, raced, and, crucially, feminine. Meanwhile, material processes such as impressing coins or spinning flax for linen shaped ways of conceiving an interiorized deep subjectivity in Irish fiction during the rise of the individual in late eighteenth-century ideology. Revising recent models of character depth and interiority that take English novel forms as their starting point (Deidre Lynch’s in particular), I show how Ireland’s particular material and colonial contexts demonstrate the need to refit the dominant, Anglocentric understanding of deep character and novel development. These four material objects structure Irish character’s gradual interiorization, but, unlike the English model, they highlight a politically resistant, inaccessible depth in Irish character that is shadowed by gendered, colonial violence. I show how, although ostensibly inert, insignificant, or domestic, these objects invoke Ireland’s violent history through their material realities—such as the way a coin was minted, when a mantle was worn, or how flax was prepared for spinning—which then impacts the very form of Irish characters in literary texts. My readings of these objects and their literary manifestations challenge the idea of the inviolable narrative and defend the aesthetics and complexity of Irish characters in the long eighteenth century. In the case of particular texts, I also consider how these objects’ agency challenges the ideology of Britain’s imperial paternalism. I suggest that feminized Irish objects can be feminist in their resistant materiality, shaping forms of Irish deep character that subvert the colonial gaze. Using Ireland as a case study, this dissertation demonstrates how theories of character and subjectivity must be grounded in specific political, material contexts while arguing that a deeper engagement with Irish materiality leads to a better understanding of Irish character’s gendering for feminist and postcolonial analysis.