•Recently developed generalised phase-field fracture model is employed.•Realistic microstructural geometries of nodular cast iron are analysed.•Model is able to recover brittle/ductile fracture in monotonic and fatigue regime.•By changing material properties, a brittle to ductile fracture transition is observed.•Framework is able to solve contact problems coupled with fracture analysis. The aim of this work is to model complex fracture and fatigue processes in microstructural geometries of nodular cast iron. Herein, recently developed generalised phase-field formulation for modelling fracture in brittle and ductile solids subjected to both monotonic and cyclic loading is employed. Three different sized microstructural specimens are analysed using different modelling options to investigate the transition between brittle and ductile fracture material behaviour. The results demonstrate the ability of the proposed model to reproduce crack nucleation and complex crack propagation patterns. Moreover, the low- and high-cyclic fatigue regime features are presented in terms of fracture patterns and Wöhler-type curve.