This portfolio comprises a culmination of research work spanning three years of full-time training on the Practitioner Doctorate course in Psychotherapeutic and Counselling Psychology (PsychD) at the University of Surrey. My research comprises three research reports: a literature review, and two qualitative studies. The literature review explored how the phenomenon of uncertainty translates to the field of counselling psychology, specifically the identity of counselling psychologists and its application within therapeutic practice. The first empirical study used Interpretative Phenomenological Analysis to analyse counselling psychologists’ experiences of uncertainty in therapeutic practice. The analysis revealed four major themes: ‘The Ethereal Nature of Uncertainty in Life’ ii) ‘Uncertainty is Core to Therapeutic Practice’ iii) ‘A Process of Negotiation: Engaging with the Tensions’ iv) ‘Facilitating the Art of Improvisation: A Dance between Being-With and Doing-To’. The second empirical study used Constructivist Grounded Theory to analyse the actions, processes and implicit subjective meanings implicated in how practitioners engage with uncertainty in therapeutic practice. Analysis revealed three interrelated core-categories: ‘Expressing an Attitude’, ‘Cultivating Different Ways of Being’, and ‘Engaging in a Constantly Unfolding Process of Negotiation’. Clinical implications for both empirical studies are discussed in light of their findings.