Elucidating the performance of collaborative development within the Beijing Tianjin Hebei (BTH) region and developing an understanding of mechanisms underlying this process are of paramount importance to regional sustainable development as well as for the realization of Chinese national strategy. Thus, utilizing socioeconomic data for 13 districts within the BTH region between 2000 and 2014, this study applies the Gini coefficient alongside the technique for order preference by similarity to an ideal solution (TOPSIS) method supported by the entropy weight model and impulse response functions in order to assess the performance of collaborative development in this region and elucidate underlying mechanisms. The results of this study reveal that collaborative development within the BTH region has tended to slowly increase over time, but with fluctuations. Although some progress has been made in promoting urbanization, constructing traffic networks, protecting the environment, and improving living standards, very significant expansion space nevertheless remains for further improvements. The collaborative development of this region has also been increasingly affected by globalization, with either the equalization of per capita fixed asset investment or fiscal expenditure exerting a definite impact. The results show that although the equalization of per capita fixed asset investment boosts collaborative development at the start of this process, it is likely to impede it over longer time scales, while the equalization of per capita fiscal expenditure will contribute to this process within the BTH region over both the short and long term. A number of policy suggestions are therefore proposed in this paper to promote smooth collaborative development of the BTH region, including optimizing investment structures and establishing an ecological compensation mechanism.