A 58-year-old attorney apparently denied a chance to interview for a job because he had too much experience may pursue a claim for unintentional age bias.

The April 26 decision by a Chicago-based federal appeals court creates a divide among the federal circuits over whether federal age discrimination law protects job applicants—and not just existing employees—from the unanticipated but unequal consequences of a facially neutral employment policy. Some have questioned whether permitting job applicants 40 and over to sue for...