The aim of this study is to improve the connectivity and microstructural control of bulk MgB2 via admixed in situ and ex situ syntheses and their effect on flux pinning behavior. Different weight percentages with the ratio of x wt.% ex situ powder were added to 1.0 g in situ powder via a solid state synthesis process where x = 0, 15, 20, 25, and 30, respectively. MgB2 was verified as the predominant phase in all of the samples by X-ray diffraction. With the addition of ex situ powder, magnetization measurements revealed a modest drop in critical temperature, Tc, from 38.5 to 37.8 K. At 20 K, the self-field critical current density, Jc, increased as the co-addition levels increased, owing to enhanced grain coupling. With a 20 wt.% co-addition level, the largest self-field Jc achieved is 348 kA/cm2 showing field dependent Jc of the co-added samples at 20 K is greater than that of the pure sample. The current findings suggest that a small quantity of ex situ powder added to the admix portion of Mg and 2B during synthesis can improve flux pinning and Jc. The reduction in the void volume which enhanced the connectivity of the sintered bulk samples was observed by scanning electron microscopy. Our results show that ex situ-in situ co-synthesis develops the superior connectivity potential of MgB2 bulk superconductor.