We investigated the effect of clinical and subclinical T cell-mediated rejection (C-TCMR and SC-TCMR) on allograft histology, function, and progression. Adult kidney recipients with 2 protocol biopsies were divided into No-TCMR on biopsies (n = 104), SC-TCMR (n = 56), and C-TCMR (n = 32) in at least 1 biopsy. Chronicity (ci + ct + cg + cv) scores, renal function, and the burden of renal disease measured by area under the curve (serum creatinine, mg mo/dL) were compared. Baseline characteristics were similar except for mean donor age and Kidney Donor Profile index scores. Patients with C-TCMR had higher mean serum creatinine, lower mean estimated glomerular filtration rate, and higher area under the curve with 95% confidence interval (75.2 [67.7-82.7]) as opposed to patients with SC-TCMR and No-TCMR (58.3 [53.6-62.9], 65.1 [58.8-71.5]), P = 0.0004. Chronicity scores were higher at 3 months in C-TCMR (2.30 ± 1.58) compared with SC-TCMR (2.02 ± 1.42) and No-TCMR (1.31 ± 1.18), P = 0.0001 and also at 12 months. At last follow-up, 18.8% patients with C-TCMR had ≥50% decline in estimated glomerular filtration rate from 3 months compared with 7% and 1% among No-TCMR and SC-TCMR groups (P = 0.038). Multivariate analyses revealed higher odds of Δ-creatinine ≥ 0.5 mg/dL from 3 months to last follow-up for C-TCMR (3.39 [95% confidence interval, 1.25-9.20]) versus No-TCMR (P = 0.016). Kidney transplant recipients with C-/SC-TCMR have heightened early allograft chronicity and worse renal function compared with those with No-TCMR. Progressive renal dysfunction was noted among patients with C-TCMR as opposed to SC-TCMR and No-TCMR.