Thermoelectric materials are considered as cleanest source of energy generation by converting waste heat into electricity. Oxides are attractive because of their environmentally benign nature, low fabrication cost and better stability at high temperature compared to other metal-based thermoelectric materials. However, the challenges in oxide thermoelectrics are manifold as figure of merit, ZT values of oxides suffer from lower electrical conductivity as well as relatively higher thermal conductivity compared to state-of-the-art materials like chalcogenides. Especially, achieving ZT>1 remain elusive for n-type bulk oxide thermoelectrics. Recently, we have put forward a strategy of boosting the electron transport by inducing semiconductor to metal transition in Nb doped SrTiO3 (STN) by synthesizing nanocomposites with graphene oxide (GO). We could enhance electrical conductivity remarkably by gradual incorporation of GO in the matrix of STN, which changed its semiconductor (dσ/dT>0) behavior into metallic (dσ/dT<0) for more than 1 wt% GO content. GO sheets embedded in the grain boundaries of polycrystalline STN facilitated electron transport without increasing much impact on its thermal conductivity, resulting in 50 times ZT enhancement due to GO incorporation. Furthermore, we have manipulated the metal-semiconductor transition in STN by inducing enough strain as a result of graphite inclusions in STN matrix and we reported the first experimental demonstration of ZT>1 in oxide thermoelectrics. Introduction of conductive graphite inclusions in STN matrix has led to a surge in electrical conductivity due to 21-times increase in weighted mobility of electrons resulting in high thermoelectric power factor ~5400 µW/mK2, which is ~16-times higher than that of pure STN. Furthermore, we could restrain the increase in thermal conductivity by attaining enhanced Umklapp scattering along with phonon-glass-like temperature-independent phonon mean-free-path above Debye temperature. We have achieved the maximum ZT ~1.42 in STN+0.5wt% G composite. Our proposed way of designing rare-earth-free composites with graphite can potentially open up the possibility of fabricating novel high-temperature thermoelectric generators.