One key challenge in heterogeneous cellular networks is the presence of wireless backhaul links whose resources must be jointly allocated with those of the radio access network. In this paper, a novel approach for joint backhaul and radio resource allocation in a two-tier small cell network is proposed. The problem is formulated as a Stackelberg game, in which the macrocell base station (MBS) acts as a leader and overlaid picocell base stations (PBSS) as followers. In this game, the MBS maximizes its sum rate transmission by properly allocating the subcarriers over the backhaul links and the PBSS seek to maximize their transmission rate by allocating power and the subcarriers. A self-backhauling model and an orthogonal frequency allocation between the backhaul and the access links are adopted, in which the subcarrier allocation over the backhaul and the access links will be captured in the leader's and followers' optimization problems, respectively. The optimal power allocation problem is studied for the followers problem. Furthermore, the uniqueness of the Stackelberg equilibrium point is investigated. Simulation results show the effectiveness of the proposed algorithm which yields up to 14.2% and 24.9% transmission rate improvement compared to the baseline method.