BSTRACTWe identify the state-associated cohesive energy and band filling as descriptors to quantify the site-to-site chemical bonding and magnetic moments of high-entropy alloys (HEAs). We find that the s-state cohesive energy is indispensable in determining the bonding-strength trend while the s-band filling is effective in determining the magnetic moments of CrMnFeCoNi HEAs. This unusual behavior stems from the localized and transferred itinerant electrons. Our study establishes a fundamental physical picture of chemical-bonding and magnetic interactions of HEAs and helps design advanced structural alloys.