This paper looks at the use of design practices in start-up firms for the creation of strategic advantage through product/service innovation. Start-ups face non-negligible challenges during the early-stage of development. The research questions examined to what extent design practices can provide the leverage needed to face these challenges. A 4-day Innovation by Design Challenge workshop provided the field for the research carried out. Participants were start-up firms each working together with two designers to form six teams. Methods used included: observation for the mapping of team activities; a short self-report questionnaire and; pre- and post-workshop semi-directed interviews with the start-ups. The findings support the idea that design practice integration into the initial development of a start-up can indeed provide a lever for success and provide the start-up with the strategic vision needed to go through the early-stage and bring their products/services to market successfully.