In this paper, we compute αs corrections to the matching coefficients of the dimension-six operators in the heavy quark expansion of the inclusive semileptonic heavy hadron decay rate and leptonic invariant mass spectrum with a massless quark and both a massive or massless lepton in the final state, analytically. The obtained results can be applied to the inclusive semileptonic B → X_uℓν¯_ℓ (ℓ = e, μ, τ) and D → Xℓν¯ℓ (ℓ = e, μ) decays. The main application of our results is the background subtraction of the B → X_uℓν¯_ℓ decay in the measurement of the B → X_uℓν¯_ℓ decay, which is important for the precise extraction of V_cb and R(D(^∗)). They also play a role in the computation of lifetimes of heavy hadrons.