We present a detailed study of the young massive star cluster Westerlund 2 (Wd2) using a high-resolution multi-band survey observed with the Hubble Space Telescope. With an estimated mass of ~4*10^4 Solar masses, Wd2 is one of the most young (~1 Myr) star clusters in the Milky Way and contains a rich pre-main-sequence population. We show that the mass accretion rate of the pre-main-sequence stars is reduced in proximity to the cluster’s massive O stars, which are eroding their circumstellar disks. We find that Wd2’s mass function is flatter than the canonical slope of the initial mass function. The cluster shows mass segregation, which is likely primordial given its young age.