Institutional narratives, appealing both to the intellect and the imagination, are powerful mechanisms of entrenchment. Drawing upon close examination of legislative debates, interview transcripts and official documents, this article analyses institutional narratives of the British National Health Service and American Medicare and Medicaid. These narratives take the form of epics, featuring founding heroes, adversaries, stewards, saviours and other characters, and are re-told on multiple occasions, and especially on anniversaries of the founding date. In the process, certain elements of history are remembered and others forgotten. The myth of the NHS as a single national institution obscured much of the complexity and compromise that went into its founding and subsequent development, but preserved fidelity to its founding principles. In the US, the dominant narrative belonged to Medicare, while Medicaid featured as an afterthought. In the case of the NHS, narrative entrenchment served to preserve universal access to comprehensive health care. In the case of American Medicare, entrenchment preserved the original mission of the institution but kept it from expanding to a broader swathe of the population, even as its less-entrenched companion Medicaid provided a vehicle for coverage of an increasingly wide range of population groups. A distinct Medicaid narrative developed only after incremental expansion was well underway.