We present a detailed study of AGN-driven outflow in the narrow-line Seyfert galaxy NGC 4051, using observations from the Hubble Space Telescope and Apache Point Observatory’s ARC 3.5m Telescope. We find a distinct conical structure in the Wide Field Camera 3 (WFC3) [O III] image which illustrates the blueshifted part of the AGN-ionized bicone in the narrow-line region (NLR). We measure the kinematics of ionized gas from spatially resolved [O III] λ5007 emission lines in long-slit spectra and find up to two blue-shifted velocity components in the NLR and extended NLR (ENLR). We also identify a moderate-density intermediate and a high-density broad component close to the nucleus. To quantify the true extents and velocities of the AGN ionized gas and outflow, we model the observed velocities and determine the geometry of the outflow bicone. We find evidence of AGN ionization up to ~600 pc and outflowing clouds with velocities of ~450 km/s up to ~400 pc to the NE of the nucleus. Finally, we compare our observations with radiative driving and gravitational deceleration models using the host galaxy mass distribution and solve for the launch radii for the observed outflowing clouds.