There has been substantial investment by governments and charities in the UK in the development, diffusion and evaluation of innovative practice models and systems to safeguard and support vulnerable children, young people and families. However, understandings of the processes of innovation within the sector are still at a relatively early stage—for example, in relation to what might be expected or planned for at each stage of an innovation journey. As a result, best use may not always be made of opportunities to address deficiencies in provision. To inform this knowledge gap, the literature was reviewed regarding innovation processes and trajectories within children’s social care (statutory and voluntary settings) and within the field of social innovation more widely. Ten modellings of the stages of innovation were identified and synthesised into a directional map of six stages that might be commonly expected: mobilising, designing, developing, integrating, growing and system change. This trajectory framework poses key questions for innovators to consider at each stage to inform planning and determine if, when and how an innovation should progress further.