In this paper, we address a physics-based analytical model of electric-field-dependent electron mobility (μ) in a single-layer graphene sheet using the formulation of Landauer and Mc Kelvey's carrier flux approach under finite temperature and quasi-ballistic regime. The energy-dependent, near-elastic scattering rate of in-plane and out-of-plane (flexural) phonons with the electrons are considered to estimate μ over a wide range of temperature. We also demonstrate the variation of μ with carrier concentration as well as the longitudinal electric field. We find that at high electric field (>106 Vm-1), the mobility falls sharply, exhibiting the scattering between the electrons and flexural phonons. We also note here that under quasi-ballistic transport, the mobility tends to a constant value at low temperature, rather than in between T-2 and T -1 in strongly diffusive regime. Our analytical results agree well with the available experimental data, while the methodologies are put forward to estimate the other carrier-transmission-dependent transport properties. © 1963-2012 IEEE.