In this article, we present a hierarchical model for doped single-wall carbon nanotube (SWCNT) for on-chip interconnect application. We study the realistic CVD grown SWCNT with defects and contacts, which induce important resistance values and worsens SWCNT on-chip interconnect performance. We investigate the fundamental physical mechanism of doping in SWCNT with the purpose of improving its electrical conductivity as well as combining mitigating the effects of defects and large contact resistance. The atomistic model provides insights on statistical variations of the number of conducting channels of doped SWCNT and SWCNT resistance variation with a various number of vacancy defects configurations. Based on atomistic simulations, we develop circuit-level models to simulate SWCNT interconnects and understand the impact of doping, defects, and contacts. Simulation results show an 80% resistance reduction by doping. Additionally, we observe that doping can mitigate the effects of defects and limited impact on contact resistance.