Short-yearling steer of known genotypes-straightbred Hereford (100H, n = 80) 75% Hereford x 25% Brahman (75H:25B, n = 80), and 50% Hereford x 50% Brahman (50H:50B, n = 80) were sampled serially at four time-on-feed endpoints (84, 98, 112, 126 d) to compare feedlot performance and carcass and palatability traits of Hereford and Hereford x Brahman steers. After slaughter, USDA yield grade and quality grade factors were recorded, and a portion of the longissimus muscle was removed from the left side of each carcass and fabricated into four 2.54-cm steaks for palatability analyses. Paired steaks from each carcass were aged (6 and 18 d after death), and sensory panel and shear force evaluations were performed. At a constant live weight, 100H steers had higher ADG and produced less mature carcasses with smaller longissimus muscle areas and higher marbling scores than did 75H:25B and 50H:50B steers. The 50H:50B steers had the highest (P < .05) values for dressing percentage. Loin steak tenderness and juiciness decreased (P < .05) and shear force values increased (P < .05) as the percentage of Brahman breeding increased. EXtending the postmortem aging period from 6 to 18 d improved shear force values by 20% and panel tenderness ratings by approximately 14%. Beef from steers of the three breeds responded similarly to aging. When Certified Hereford Beef (CHB) specifications were applied, steaks from 100H steers and 75H:25B steers had similar shear force values, suggesting that beef from quarter-blood Brahman crossbred steers could be included in the CHB Program without detrimental effects on product tenderness.