The objective was to explore the associations between patient involvement in the rehabilitation process and improvements in function and goal attainment in the first year after rehabilitation. The longitudinal multicenter study RehabNytte provided data from participants who had been referred to rehabilitation (n = 2113). Quality indicator (QI) pass rates (% yes) were used to assess patient involvement in the rehabilitation process. The Patient-Specific Functional Scale (PSFS) (10 = best possible) was used to assess function. The outcome QI on goal achievement (response options of yes/no) was used to assess goal attainment. Logistic regression and paired sample t-tests were used to examine associations and mean changes in function from rehabilitation admission up to 3, 6, and 12 months. Most participants (95%) were involved in goal-setting, which was positively associated with younger age (OR 0.97, 95% CI 0.95–0.99) and female sex (OR 1.87, 95% CI 1.15–3.02). Function improved over the follow-up period, with greater improvements in the active goal-setting group. Being involved in goal planning almost tripled the odds of goal attainment (OR 2.78, 95% CI 1.60–4.83) and involvement in the rehabilitation plan almost doubled it (OR 1.99, 95% CI 1.41–2.81). Most participants were involved in rehabilitation goal-setting/planning and being involved was associated with beneficial functional outcomes and greater goal attainment.