Angiotensin receptor neprilysin inhibitor (ARNI) and sodium-glucose cotransporter 2 inhibitor (SGLT2i) are emerging medical treatments for decompensated heart failure (HF) with reduced ejection fraction. In clinical practice, the combination of ARNI and SGLT2i cannot be administered owing to the poor hemodynamic status in patients with HF with reduced ejection fraction (HFrEF). This study aimed to compare different strategies of HF management for ARNI first or SGLT2i first in such a population. From January 2016 to December 2021, 165 patients were diagnosed with HFrEF and New York Heart Association functional class ≥II and already received optimal medical treatment. Ninety-five patients received the ARNI-first strategy, and 70 patients received the SGLT2i-first strategy according to the physician's choice. Age, sex, hemodynamic condition, etiologies of HF, comorbidities, serum creatinine, N-terminal pro-B-type natriuretic peptide (NT-ProBNP), echocardiographic parameters, and clinical outcomes were compared between the ARNI and SGLT2i-first strategy groups. In the SGLT2i-first group, the median interval between the addition of the second medication was longer (ARNI-first vs. SGLT2i-first; 74 [49-100] days vs. 112 [86-138] days; p = 0.044). Improvement in left ventricular ejection fraction (LVEF), change in left atrial dimension, and change in left ventricular end-diastolic and end-systolic volume (LVESV) did not differ between the two groups. The incidence of HF hospitalization, cardiovascular mortality, and all-cause mortality did not differ between the two groups. A non-significant trend of lower NT-proBNP levels (ARNI-first vs. SGLT2i-first; 1383 [319-2507] pg/mL vs. 570 [206-1314] pg/mL; p = 0.055) and significantly higher discontinuation rate of diuretic agents (ARNI-first vs. SGLT2i- first; 6.8% vs. 17.5%; p = 0.039) were noted in the SGLT2i-first group. When early combination (≤14D) compared to late combination (>14D), better positive remodeling of LVESV presented significantly in early combination subgroups. In patients with symptomatic HFrEF, SGLT2i-first strategy may provide a higher possibility of discontinuing diuretic agents than the ARNI-first strategy. Changes in LV performance, progression of renal function, and clinical outcomes did not differ between the two groups. Early combination (≤14D) provided better LV remodeling.