Abstract The objective of this study was to evaluate the effect of copper (Cu) status on response to lubabegron fumarate (Experior, Elanco, Greenfield, IN). Angus crossbred steers [n = 48; body weight (BW) = 469 ± 31 kg] were enrolled in a 77-d finishing study, housed in pens of 6, with a GrowSafe bunk (GrowSafe Systems, Ltd, Airdire, AB, Canada) in each pen and implanted (Revalor-200, Merck Animal Health, Madison, NJ; 200 mg TBA + 20 mg E2) on d 0. A 2 × 2 factorial arrangement was applied to Cu status (deficient, DEF, no supplemental Cu; or adequate, ADE, 10 mg supplemental Cu/kg DM as CuSO4) and Experior (36 mg·steer⁻¹·d⁻¹, EXP; or no Experior, NOEXP). A prior trial resulted in steers with distinct liver Cu (DEF and ADE were 42 ± 21 and 193 ± 31 mg Cu/kg DM, respectively). Experior was fed from d 37 to d 73, and cattle harvested on d 78. Body weights were collected on d -1, 0, 37, 55 (mid-Experior), 76 and 77. Blood was collected on d 0, 37, 55, and 76 for serum urea nitrogen (SUN), non-esterified fatty acids (NEFA), glucose, and insulin. Data were analyzed in Proc Mixed of SAS as a factorial design, with steer as the experimental unit (n = 12 per treatment). From d 0-37, DEF daily gain and feed efficiency (G:F) were greater than ADE (P < 0.01), while dry matter intake (DMI) did not differ (P = 0.36). Overall DMI was greater in ADE than DEF (P = 0.04) and not affected by Experior (P = 0.13). Carcass-adjusted average daily gain was not affected by Cu or Experior (P ≥ 0.21). Deficient steers had greater carcass-adjusted G:F than ADE (P = 0.02). Hot carcass weight was greater in EXP (P = 0.04), but post-hoc analysis of the Cu x Experior effect (P = 0.2) reveals this was driven by DEF-EXP (15 kg over DEF-NOEXP) rather than ADE-EXP (4 kg over ADE-NOEXP). Marbling tended to be greater in ADE (P = 0.06) and was unaffected by Experior (P = 0.14). The revised quantitative insulin sensitivity check index displayed an EXP x Day effect (P < 0.01) where NOEXP was consistent across days and EXP had greater insulin sensitivity during the Experior period. Serum urea nitrogen was affected by Cu × Experior × Day (P = 0.01), where DEF-NOEXP had lesser d 0 SUN than all others, and EXP decreased on d 55 while NOEXP increased steadily during the finishing phase; by d 76 DEF-EXP remain lesser than NOEXP treatments with ADE-EXP being similar to all others. These data suggest Cu concentration influences steer response to lubabegron fumarate, and more research is needed to determine the cause of this.