Background: Few studies have reported socio-economic status and functioning in patients newly diagnosed with bipolar disorder (BD) and their unaffected siblings (US). Methods: Socio-economic status and functioning were compared in a cross-sectional clinical study including 382 patients newly diagnosed with BD, 129 of their US, and 200 healthy control individuals (HC). Results: Socio-economic status was lower in patients newly diagnosed with BD compared with HC within educational achievement, employment status, workability and relationship status (p < 0.001, OR between 0.02 and 0.53). Regarding US and HC, US had lower educational achievement (p < 0.001, OR = 0.27 [0.16; 0.46]), as the only affected socio-economic outcome. Functioning was substantially impaired according to the Functional Assessment Short Test (FAST) (p < 0.001, Cohen's d = 2.12) and Work and Social Adjustment Scale (WSAS) (p < 0.001, Cohen's d = 2.76) in patients newly diagnosed with BD compared with HC. US expressed the same pattern with impaired overall functioning. Within patients, the impaired functioning was associated with a longer illness duration. Limitations: Patients had an illness duration of 10.5 [IQR: 6.1; 16.2] years, even though they were included shortly after a diagnosis of BD (0.3 [IQR: 0.1; 0.7] years), highlighting the obstacles of research in illness onset of BD. Conclusions: Patients newly diagnosed with BD, and to a lesser degree their US, exhibit lower socio-economic status and impaired overall functioning. These findings emphasise the importance of early diagnosis, treatment and focus on functional recovery and stress that intervention strategies and further research in high-risk individuals are needed.