Background <p>Digitalisation is transforming healthcare delivery but has introduced new psychosocial and organisational demands. Older workers may be particularly vulnerable to cognitive load, technostress, and reduced well-being during rapid digital transitions. However, evidence focused on primary care professionals aged ≥ 50 years remains limited. This study examined how workplace digitalisation is related to work organisation and mental health in this group.</p> Methods <p>A mixed-methods case study was conducted in a personalised primary care unit in northern Portugal. A self-administered questionnaire was completed by 24 professionals aged ≥ 50 years (92% of eligible staff). Institutional documents were analysed to contextualise organisational policies. The quantitative data were analysed descriptively via group comparisons (χ² tests or exact tests, as appropriate), whereas the qualitative data from the open-ended responses and documents were examined via thematic content analysis. The findings were integrated through triangulation.</p> Results <p>The participants recognised the benefits of digitalisation for organisational performance and efficiency (91.7%). However, 62.5% reported increased work-related stress, and 33.4% perceived a worsening of work–life balance. Only 25.0% felt that they had sufficient time to learn and adapt to new technologies. Among the respondents to the privacy-related items (<i>n</i> = 23), 60.9% agreed that the institution had clear data protection policies and that 60.9% felt confident about data security; however, only 26.1% reported receiving adequate training on data privacy (52.2% disagreed). The only significant difference by professional role concerned perceived time for adaptation: clinical staff more frequently disagreed that they had sufficient time (11/16, 68.8%), whereas nonclinical staff were mostly neutral (5/7, 71.4%) (Fisher–Freeman–Halton exact test, <i>p</i> = 0.003). The qualitative analysis identified four themes: digital acceleration and loss of autonomy; emotional fatigue and reduced human connection; learning inequalities by age and role; and collective coping and resilience. Documentary analysis revealed a stronger institutional emphasis on technological modernisation than on staff mental health.</p> Conclusions <p>Digitalisation in primary care was experienced by older professionals as both an opportunity and a source of psychosocial strain. Without adequate training, protected learning time, participatory implementation, and explicit occupational mental health strategies, digital transformation may exacerbate stress and inequalities within an ageing workforce. Integrating human-centred design and age-sensitive training into digital health policies may support more sustainable and equitable primary care systems.</p>