Traditional approaches to supporting older adults in adopting and maintaining an active lifestyle have largely failed. The previously proposed "Staircase Approach" offers a new foundation for developing interventions and public health strategies; this approach includes Step 1 (changing sedentary behaviour) and Steps 2 to 4 (incorporating more physical activity of increasing levels of intensity). In this systematic search and review, we aimed to inform the co-creation of a novel Staircase Approach intervention for community-dwelling, inactive older adults, primarily focussed on Step 1. A systematic search was performed across six databases (MEDLINE, PsycInfo, CINAHL, Cochrane CENTRAL, SPORTDiscus and Scopus). After duplicates were removed, 3427 titles and abstracts were screened. Fourteen articles (including 17 intervention groups) were included after full-text review. Five were randomized controlled trials, three compared two interventions and six were single-arm studies. Sample sizes ranged from 9 to 176 participants, and included 617 older adults at baseline. Mean age of samples ranged from 64.3 (standard deviation [SD] 3.8) to 85.1 (SD 6.2) years, while the intervention length ranged from less than one day to 6 months. Sedentary time interventions are well accepted; most studies had completion rates above 80%. Based on findings from within-group comparisons, half of the studies showed a reduction in sedentary time (6/12 groups) and half showed an increase in physical activity (6/12 groups). Based on findings from between-group comparisons, 2 out of 5 intervention groups showed improvements in sitting time and physical activity outcomes compared to controls. Satisfaction and adherence to interventions were generally high. Sedentary time interventions for older adults show promise and point to several components that may be included in an intervention focussed on Step 1 of the Staircase Approach.