Background <p>Type 1 diabetes is the most common endocrine metabolic disorder in childhood and adolescence. Lifestyle education can play a key role in managing this condition effectively. Continuous care provided by nurses and related healthcare organizations using various approaches can significantly improve the overall health of children and adolescents with chronic illnesses. Given the rising prevalence of type 1 diabetes and its long-term complications, promoting healthy lifestyle behaviors in this population is a significant public health priority. Therefore, this study was conducted to evaluate the effect of a continuous care model on the lifestyle of adolescents with type 1 diabetes.</p> Methods <p>This experimental study was conducted from January to September 2024. A total of 68 adolescents aged 12 to 18 with type 1 diabetes, who were referred to clinics at specialized children’s hospitals in Tehran, were selected through purposive sampling and then randomly assigned to either an intervention or control group. The intervention group received training through a continuous care model delivered over five 45-minute sessions, while the control group received no intervention. Data were collected using demographic questionnaires and Walker’s Health-Promoting Lifestyle Profile, and analyzed using SPSS version 27.</p> Results <p>Before the intervention, lifestyle scores were similar between the intervention (97.23 ± 35.42) and control (96.79 ± 30.96) groups (<i>P</i> = 0.950). After the intervention, the mean lifestyle score in the intervention group increased significantly to 149.91 ± 25.28, compared to 97.21 ± 28.47 in the control group (<i>P</i> = 0.0001). The intervention group also showed a significant improvement from baseline (<i>P</i> = 0.0001). Most adolescents in both groups initially had undesirable or relatively desirable lifestyle scores, with no significant difference between groups (<i>P</i> &gt; 0.05). After the intervention, the lifestyle classification improved significantly in the intervention group (<i>P</i> ≤ 0.05), while no change was observed in the control group.</p> Conclusions <p>The continuous care model significantly improved the lifestyle of adolescents with type 1 diabetes. Due to its simplicity, cost-effectiveness, and positive outcomes, this model can be effectively implemented by nurses and healthcare providers in both clinical and community settings to support long-term lifestyle improvements among adolescents with chronic conditions.</p> Clinical trial number <p>Not applicable.</p>