How do you handle an underperforming team member?

Handle it as diagnosis before judgement, and show that you act rather than avoid.

• Establish the facts first. What specifically is below expectation, measured how, and over what period. Vague dissatisfaction is not a performance issue and cannot be addressed.
• Find out why. Genuinely — is it a skills gap, unclear expectations, a workload or tooling problem, a mismatch between the role and their strengths, or something outside work? The right response differs entirely, and managers who skip this step usually address the wrong problem.
• Have the conversation early and directly. Specific examples, the standard expected, and clear agreement on what changes. Delaying is unkind — it denies someone the chance to fix something they may not know is a problem.
• Agree a plan with a timeframe and support, and document it. Follow up on the dates you set.
• If it does not improve, act. Moving them to a better-fitting role or exiting them is a legitimate outcome, and a team carrying sustained underperformance loses its strongest people first.

Note: Saying that you would first ask whether you had set them up to fail — unclear brief, no feedback, wrong role — shows genuine management maturity.