Soccer support staff operate under demanding schedules and high-performance environments while guiding players’ movement, sleep, and nutrition; however, their own lifestyle behaviours remain under-researched. This exploratory study assessed adherence to the Canadian 24-Hour Movement (24HM) guidelines and its association with diet quality (DQ) in professional and semi-professional soccer support staff. Methods: A cross-sectional survey collected data from 236 staff in the United Kingdom and Spain. Movement behaviours were measured using the Whole Day Matters Toolkit and DQ using the validated Mini-EAT questionnaire. A graded 24HM score (0–8) summed binary adherence across four general (MVPA, LPA, sedentary time, sleep) and four secondary (muscle-strengthening, sedentary interruptions, screen time, sleep–wake time) behaviours. Associations with DQ were estimated using adjusted multiple linear regression. Results: Only 7.6% of participants met all eight guidelines. Each one-point increase in the graded score was associated with 0.89-point higher DQ (95% CI 0.29–1.49, p = 0.004), with stronger associations observed for secondary behaviours (β = 1.27, p = 0.006) than for general behaviours (β = 0.38, p = 0.50). Conclusions: A graded 24HM scoring approach showed a graded association with DQ in soccer staff, with secondary movement behaviours showing a stronger association. All findings should be interpreted as exploratory and hypothesis-generating. ClinicalTrials.gov: NCT06771752.