X-ray absorption measurements and large-scale molecular dynamics simulations are used to investigate the storage capacity of hydrogen in cluster-assembled carbon films. Experimental results show that nanostructured carbon exposed to H-2 at 0.12 MPa for 3 h at room temperature can store up to 1.5 wt % of hydrogen. These experimental results are in good quantitative agreement with the computational data. Both experiments and simulations confirm that hydrogen is chemisorbed on the carbon. The simulations provide information about the spatial distribution of the sorption sites of atomic and molecular hydrogen.