Embodiments of a gas turbine engine including a finger-foil seal are provided, as are embodiments of a finger-foil seal. In one embodiment, the finger-foil seal includes an aerodynamic foil having a generally annular body through which a first opening is formed. A finger seal retention structure is disposed around the aerodynamic foil. A finger seal backing spring is coupled to the finger seal retention structure and extends radially inward therefrom to contact an outer circumference of the aerodynamic foil. A first anti-rotation pin extends radially from the finger seal retention structure and into the first opening formed in the aerodynamic foil to inhibit rotation of the aerodynamic foil during operation of the finger-foil seal.