What do employers actually ask in a reference check?

Formal reference checks at large companies are usually narrow. Corporate policy commonly limits HR to confirming dates of employment, job title, and occasionally whether the person is eligible for rehire, because volunteering opinions creates legal risk. That eligible-for-rehire field is the one that carries weight, since a no communicates a great deal without stating anything actionable. Personal references you provide are different: those are people you selected, and hiring managers know it, which is why a strong reference matters less than an unenthusiastic one hurts.

What actually shapes hiring decisions is the informal check, the call to a mutual contact who was never on your list. That conversation is unconstrained by policy and is where reputation genuinely operates, which is the practical reason for leaving jobs well. A few useful specifics: ask your references in advance and tell them what role you are pursuing so they can be relevant, warn them when to expect contact, and never list someone you have not confirmed will be positive. Background checks are a separate process governed by the Fair Credit Reporting Act, which requires your written authorization, requires the employer to give you a copy of the report and a chance to dispute before taking adverse action, and limits how far back certain information can be reported. If a check surfaces something wrong, you have a legal right to contest it.