Abstract Background Poor mental health may lead to labour market insecurity including precarious employment and vice versa. Less is known of how mental health is associated with cumulative engagement in precarious employment over the working career. We examined how the working career is expected to be distributed into precarious and other types of employment by history of mental-health-related sickness absence. Methods We used a register-based 70% population sample to examine wage-earners living in Finland in 2018. Applying the Sullivan method, we calculated the expectancy of precarious and non-precarious employment between age 25 and 63 (N = 1268666) based on a novel measure (score with items on temporariness, agency employment, multijob holding, underemployment and income level) and limited employment (due to which precariousness could not be assessed) among those with and without compensated (granted after 10 weekdays) sickness absence due to mental disorders in the past five years (mental SA history). Results Precarious employment expectancy was higher among those with than among those without a mental SA history (2.5 vs. 1.5 among men and 3.5 vs. 2.8 years among women). The difference in the limited employment expectancy was in the same direction, but much larger among men (6.5 vs. 3.3 among men and 4.4 vs. 3.4 years among women). Men with a mental SA history were expected to spend almost a fourth of their working career with either precarious or limited employment, whereas for men without such a history the number was 13%. Conclusions Individuals with mental disorders have notable accumulation of precarious employment over the working career. They also spend excessive time with limited employment, which may have similar elements as precarious employment and reflect broader labour market insecurity. Attempts should be made to ensure that insecure employment conditions among people with mental health problems do not further deteriorate their health and work ability. Key messages • People with mental disorders spend a disproportionate part of their working career either precariously employed or facing other insecurities in the labour market. • Interventions aiming to promote health and work ability should take into account the interplay between poor mental health and poor employment conditions.