To fulfill the beam quality and operational requirements of the SwissFEL project, currently under construction at the Paul Scherrer Institut, a new RF photocathode gun for the electron source was designed and manufactured in house. A 2.6 cell S-band gun operating with near-perfect rotationally symmetric RF field was designed to operate with a 100 MV/m cathode field at a repetition rate of 100 Hz with average power dissipation of 0.9 kW with pulse duration of 1 μs. The first SwissFEL-gun is now fabricated and installed in the SwissFEL Injector Test Facility (SITF). The frequency spectrum and field balance, through beadpulling, have been directly verified in-situ and then the gun has been operated with high-power RF. The results of beadpull measurements and high-power tests are presented and discussed. In addition the emitted dark current was also measured during the high-power tests and the charge within the RF pulse was measured as a function of the peak cathode field. Faraday cup data were taken for cathode peak RF fields up to 100 MV/m for the case of a diamond-milled polycrystalline copper cathode.