{gamma} Cas is the prototypical classical Be star and is recently best known for its variable hard X-ray emission. To elucidate the reasons for this emission, we mounted a multiwavelength campaign in 2010 centered around four XMM-Newton observations. The observational techniques included long baseline optical interferometry (LBOI) from two instruments at CHARA, photometry carried out by an automated photometric telescope and H{alpha} observations. Because {gamma} Cas is also known to be in a binary, we measured radial velocities from the H{alpha} line and redetermined its period as 203.55+/-0.20 days and its eccentricity as near zero.