Leaderless group discussions (LGDs) constitute one of the oldest assessment center exercises. In recent times, their added value has sometimes been questioned in light of trends to streamline assessment centers. The purpose of the present study is to examine the incremental validity of LGD ratings over cognitive ability scores and personality ratings for the prediction of extrinsic career success (i.e., promotion speed and number of promotions). We investigated this issue in the context of the promotion of French naval officers (N = 93) in an academy for high‐level executive positions over a 10‐year period. Results indicated that LGD ratings accounted for incremental variance in the prediction of promotion criterion measures, beyond cognitive ability and personality test scores. These results confirm that LGD ratings provide a unique contribution to the prediction of extrinsic career success in high‐level executive positions.