In this paper, we introduce the ψ-Hilfer pseudo-fractional operator, motivated by the ψ-Hilfer fractional derivative and the theory of pseudo-analysis. We investigate a wide class of important and essential results for pseudo-fractional calculus in a semiring ([a, b], ⊕,) and some particular cases are discussed. Specifically, we present a class of pseudo-fractional operators which are particular cases of the ψ-Hilfer pseudo-fractional operator. In addition, we present the pseudo-Leibniz-type rules I and II and pseudo-Leibniz rules and some particular cases of Leibniz-type rules I and II are discussed. Finally, we obtain formulas for the Hilfer pseudofractional derivative, for the pseudo-Laplace transform, and for the g-integration by parts of the ψ-Hilfer pseudo-fractional operator.