Ring-opening metathesis polymerization (ROMP) mediated by Grubbs’ first-generation catalyst [G1, (PCy₃)₂(Cl)₂RuCHPh] and Grubbs’ third-generation catalyst [G3, (H₂IMes)(Cl)₂(pyr)₂RuCHPh] can exhibit living characteristics for some monomer classes, most commonly substituted norbornenes. Here, we studied how various anchor groups, the series of atoms connecting the polymerizable norbornene unit to a functional group, affect livingness in ROMP in a series of small-molecule exo-norbornene monomers. We first designed and calculated the HOMO energy of 61 monomers using density functional theory methods, finding that these energies spanned a range of 25 kcal/mol. We then performed kinetics experiments using ¹H NMR spectroscopy to measure the propagation rate constant (k_p,obs) under identical conditions for eight selected monomers with different anchor groups across the range of HOMO energies. We observed a positive correlation between the HOMO energy or the HOMO/LUMO energy gap and measured k_p,obs values for both catalysts, revealing a 30-fold and a 10-fold variation in k_p,obs values across the series for G1 and G3, respectively. Interestingly, we observed a plateau for the three monomers with the highest HOMO energies for G3 catalyst, suggesting that above a certain level, the HOMO energy no longer influenced the rate-determining step under the conditions studied here. Chelation studies revealed that only one of the eight monomers showed measurable binding of electron-rich groups on the monomer to the catalyst, but with no apparent effect on k_p. Finally, we utilized ¹H NMR spectroscopy to measure the rate of catalyst decomposition in the presence of each monomer, a key termination pathway in ROMP. Ultimately, we determined that the anchor group did not substantially affect catalyst decomposition, a proxy for the termination rate constant (k_t). In sum, these combined computational and experimental studies collectively demonstrate that livingness in ROMP of exo-norbornene monomers using G1 and G3 catalysts, as measured by relative k_p/k_t ratios, is primarily controlled by the k_p of the anchor group, which is correlated with the HOMO energy.