The level scheme of 51Mn has been investigated using the 28Si ( 32S ,2α1p) 51Mn fusion-evaporation reaction at 125 MeV beam energy. The γ rays were detected in the Ge-detector array Gammasphere, which was coupled to the 4π -charged-particle detector Microball and the Neutron Shell for the coincident detection of evaporated particles. Over 100 new γ -ray transitions connecting some 50 excited states have been identified. Most of the states are built on particle-hole excitations across the shell gaps at particle number N=Z=28 . The rich experimental data allows for a comprehensive comparison of core-excited states with results from large-scale shell-model calculations, which are known to provide excellent predictions for the lower-lying yrast and near-yrast levels in 1 f7/2 nuclei.