Abstract The objective of this study was to evaluate potency and timing of trenbolone acetate (TBA) administration on live performance and carcass characteristics of beef × dairy steers. A total of 6,895 beef × dairy steers initial body weight (BW) = 157 ± 5.2 kg were allotted into 30 pens, with pen as the experimental unit. Each pen was randomly assigned one of three implant treatments: 1) Revalor-IS (IS) at d 0, IS at d 80, and Revalor-XS (XS) at d 160 (IS/IS/XS); 2) Ralgro at d 0, IS at d 80, and XS at d 160 (Ral/IS/XS); or 3) Encore at d 0 and XS at d 160 (Enc/XS). Steers were blocked by arrival date, each pen was terminally sorted in three ways at 257 ± 22 days on feed and harvested at 329 ± 25 days on feed. For live and carcass outcomes, fixed effect of implant treatment and random effect of block was evaluated. Data are reported on a deads and removals out basis. Removals, morbidity, and mortality were similar (P ≥ 0.45). Steers administered TBA prior to d 160 were 5.8 kg heavier (P = 0.03) than Enc/XS steers at d 160. Final BW was not different (P = 0.78). Early administration of a TBA-containing implant resulted in an increased prevalence of bullers 2.40%, 5.18%, 6.86% (for Enc/XS, Ral/IS/XS, and IS/IS/XS) respectively; P < 0.01. Dry matter intake (DMI) was 2.3% greater (P < 0.01) in steers administered Enc/XS compared to IS/IS/XS; however, DMI as a percentage of BW, average daily gain, and feed efficiency were not different (P ≥ 0.12). Dressing percentage, hot carcass weight, heavy carcass occurrence, Longissimus muscle area, and 12th rib fat thickness were similar among all steers (P ≥ 0.28). Marbling score tended to be greatest for Enc/XS and Ral/IS/XS (P = 0.09). Enc/XS graded a greater proportion of USDA Prime and fewer USDA Select carcasses than IS/IS/XS (P < 0.05). Enc/XS and Ral/IS/XS tended (P = 0.09) to have more USDA Yield Grade (YG) 1 carcasses. While delayed administration or decreased total potency of TBA-containing implants may decrease buller incidence and improve Quality Grade, few differences were observed in live or carcass outcomes. Increased potency and earlier administration of TBA-containing implants increased prevalence of bullers, but implant treatment did not affect live growth performance outcomes. Quality Grade improved and empty body fat percentage was greater in steers administered the lowest potency and latest administration of TBA implants, with no other differences for carcass performance. Lay Summary This experiment was designed to evaluate the effects of timing and potency of trenbolone acetate (TBA) on live and carcass performance of beef × dairy steers. Administration of TBA occurred at d 0, 80, or 160 in total dosages of 320, 240, or 160 mg for IS/IS/XS, Ral/IS/XS, or Enc/XS, respectively. Morbidity and mortality were similar for implant treatment; however, percentage of buller steers increased as TBA was administered earlier and at higher dosages. Feed intake increased in steers receiving greater dosages of TBA, but no differences in feed efficiency or growth performance were observed. Final body weight, hot carcass weight, and dressing percentage were not affected by implant treatment. Aside from improved marbling score and Quality Grade for the least and latest dosage of TBA treatment, no differences in carcass characteristics were observed. These results indicate decreased dosage and delayed administration of TBA-containing implants may improve quality grade with minimal effects on live and carcass performance compared to greater and earlier TBA administration treatments in beef × dairy steers.