Background Few studies have explored evidence-based practice (EBP) knowledge, attitudes and behaviours of health professional graduates transitioning into the workforce. This study evaluated changes in these EBP domains in physiotherapists after one year of working. Method A mixed methods design was used. Participants completed two psychometrically-tested EBP questionnaires at two timepoints. The Evidence-Based Practice Profile questionnaire collected self-report EBP data (Terminology, Relevance, Confidence, Practice, Sympathy) and the Knowledge of Research Evidence Competencies collected objective data (Actual Knowledge). Changes were calculated using descriptive statistics (paired t-tests, 95% CI, effect sizes). Qualitative interview data collected at one timepoint were analysed using a descriptive approach and thematic analysis, to examine the lived experience of participants in the context of their first employment. The aim of the mixed methods approach was a broader and deeper understanding of participants’ first year of employment and using EBP. Results Data were analysed from 50 participants who completed both questionnaires at the two timepoints. After one year in the workforce, there was a significant decrease in participants’ perceptions of Relevance (p<0.001) and Confidence with EBP (p<0.001) and non-significant decreases in the other domains. Effect sizes showed medium decreases for Relevance (0.69) and Confidence (0.57), small decreases in Terminology (0.28) and Practice (0.23), and very small decreases in Sympathy (0.08) and Actual Knowledge (0.11). Seven themes described participants experience of using EBP in their first working year. Conclusions After a year in the workplace, confidence and perceptions of relevance of EBP were significantly reduced. A subtle interplay of features related to workplace culture, competing demands to develop clinical skills, internal and external motivators to use EBP and patient expectations, together with availability of resources and time, may impact early graduates’ perceptions of EBP. Workplace role models who immersed themselves in evidence discussion and experience were inspiring to early graduates.