Objectives: To assess the association between baseline HbA1c and the poor outcomes within 1 year after acute ischemic stroke. Methods: Acute ischemic stroke patients with HbA1c values at baseline (n = 2186) were selected from the abnormal glucose regulation in patients with acute stroke across China study (ACROSS). Logistic regressions were performed to assess the association between HbA1c quartiles (< 5.5% [37 mmol/mol], 5.5 to,6.1% [37 to <43 mmol/mol], 6.1 to,7.2% [43 to <55 mmol/mol], and >= 7.2% [>= 55 mmol/mol]) and the poor outcomes within 1 year. Poor outcomes were defined as all-cause mortality (modified Rankin scale [mRS] = 6) and poor functional outcome (mRS [2-6]). Results: The risk for all-cause mortality was significantly increased in HbA1c level >5.5% [>37 mmol/mol] when compared to HbA1c quartile <5.5% [<37 mmol/mol] and dramatically increased to two to three times higher in the highest HbA1c quartile >= 7.2% [>55 mmol/mol] (1-year all-cause mortality model, odds ratios [ORs] were 1.07, 1.01, and 2.45, P for trend 0.009). After the further analysis with previous diabetes mellitus (DM) and post-stroke insulin use stratified, the risk of mortality was increased across the HbA1c levels (P for trend 0.020) and dramatically augmented in HbA1c 7.2% [. 55 mmol/mol] in patients without a history of DM and without post-stroke insulin use. Discussion: Elevated HbA1c (from 5.5% [37 mmol/mol]) presenting pre-stroke glycemia status has a significant trend in increasing the risk of 1-year all-cause mortality. HbA1c >= 7.2% (>55 mmol/mol) is an independent risk predictor for 1-year all-cause mortality after acute first-ever ischemic stroke. Such an association might be altered by glycometabolism status.