Abstract We present observations, numerical simulations, and analysis from experiments in the Lithium Tokamak Experiment-Beta (LTX-β) in which the electron temperature profile (T_e (r)) shifts from flat to peaked and a tearing mode is also destabilized when the average density (n_e ^ave ) exceeds ∼10¹⁹ m⁻³. Flat T_e (r) is obtained routinely in LTX-β, with a lithium coated, low-recycling first wall, once the external fueling is stopped and density decays [Boyle et al 2023 Nucl. Fusion 63 056020]. In the present experiment, flat T_e profiles can be sustained while maintaining constant n_e ^ave below a line averaged density threshold (n_e ^ave _th ) of ∼10¹⁹ m⁻³. Above n_e ^ave _th, T_e (r) shifts from flat to peaked and a tearing mode is destabilized. Due to low recycling, the achieved n_e ^ave can be controlled precisely by external fueling and hence, a certain threshold of the edge neutral inventory from the external fueling is experimentally manifested through n_e ^ave _th . The goal of the present work is to investigate the role of edge neutrals in determining T_e (r) and MHD stability in the unique low-recycling regime of LTX-β. Our hypothesis is that the peaking of T_e (r) beyond n_e ^ave _th is due ultimately to the edge cooling by the cold neutrals beyond a critical fueling flux. At lower fueling flux, flat T_e (r) results in broader pressure profile and lower resistivity, which in turn stabilizes the tearing mode. This hypothesis is supported by edge neutral density estimation by DEGAS 2 code. Mode analysis by singular value decomposition confirms the tearing mode structure to be m/n = 2/1 (m and n being the poloidal and toroidal mode numbers). Linear tearing stability analysis with M3D-C1 predicts that plasmas with n_e ^ave > 10¹⁹ are highly susceptible to a n = 1 tearing mode. ORBIT simulations, however, confirmed that the tearing modes do not contribute to the loss of fast ions from neutral beam injection. This study shows for the first time that the neutral inventory at the edge could be one of the deciding factors for the achievability of the unique operation regime of flat T_e (r) and the excitation of tearing activity that could be disruptive for the plasmas.