This study investigates the theory for predicting Lagrangian properties including particle orbit, Lagrangian mean level, Lagrangian wave frequency, mass transport velocity, wave profile, velocity distribution and wave pressure in progressive gravity water waves at uniform depth. A series of laboratory experiments are performed to measure the trajectories of particles and the wave pressure. Asymptotic solutions up to fifth order that describe irrotational finite amplitude progressive gravity water waves are derived in completely Lagrangian coordinates. The analytical Lagrangian solution that is uniformly valid satisfies the irrotational condition, the dynamic boundary condition and the zero pressure at the free surface. The explicit fifth-order parametric solution highlights the trajectory of a water particle and the wave kinematics above the mean water level and within a vertical water column, which were calculated previously by an approximation method using an Eulerian approach. Mass transport up to fourth order associated with a particle displacement can now be obtained directly in Lagrangian form. In particular, the Lagrangian wave frequency and the Lagrangian mean level of particle motion can also be obtained, which are different from those in an Eulerian description. By comparing the present fifth-order asymptotic solution with data from laboratory experiments, it is found that theoretical results show good agreement with experimental data.