AimTo examine the level of adherence to best‐practice guidelines of interprofessional teams with acute care nurse practitioners (ACNPs) compared to interprofessional teams without ACNPs.DesignA retrospective observational study was conducted in 2023.MethodA retrospective cohort was created including 280 patients who underwent a coronary artery bypass graft and/or a valve repair and hospitalised in a cardiac surgery unit of a university affiliated hospital in Québec (Canada) between 1 January 2019 to 31 January 2020.The level of adherence to best‐practice guidelines was measured from a composite score in percentage. The composite score was created from a newly developed tool including 99 items across six categories (patient information, pharmacotherapy, laboratory tests, post‐operative assessment, patient and interprofessional teams' characteristics). Multivariate linear and logistic regression models were computed to examine the effect of interprofessional teams with ACNPs on the level of adherence to best‐practice guidelines.ResultsMost of the patients of the cohort were male and underwent a coronary artery bypass graft procedure. Patients under the care of interprofessional teams with ACNP were 1.72 times more likely to reach a level of adherence higher than 80% compared to interprofessional teams without ACNPs and were 2.29 times more likely to be within the highest quartile of the scores for the level of adherence to best‐practice guidelines of the cohort.ImpactThis study provides empirical data supporting the benefits of ACNP practice for patients, interprofessional teams and healthcare organisations.Relevance for PracticeOur findings identify the important contributions of interprofessional teams that include ACNPs using a validated instrument, as well as their contribution to the delivery of high quality patient care.Reporting MethodThis study followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Statement: Guidelines for reporting observational studies guidelines.Patient or Public ContributionNo patient or public contribution.