Satisfaction with life is considered an essential indicator of quality of life and has implications not only for parents but also for the general health of society. It is relevant to know the factors that could explain differences in parents’ satisfaction with life. The objectives of this study were to analyse the degree of satisfaction with life of a cohort of fathers 13–24 months after the birth of their child and to analyse the predictive capacity of sociodemographic, physical, psychological, and social factors on their long-term life satisfaction. This was a longitudinal study with follow-up at 6–12 months and at 13–24 months (n = 152 fathers). The Fatigue Assessment Scale, Athens Insomnia Scale, Parental Stress Scale and short version of the Dyadic Adjustment Scale were completed online at 6–12 months. Finally, Satisfaction with Life Scale was assessed between 13 and 24 months after birth. The mean score of life satisfaction of the participants 13–24 months after the birth of their child was 18.72 (SD = 3.71) and was negatively correlated with fatigue, insomnia, and stress (p < 0.01), and positively correlated with dyadic adjustment (p < 0.01). The final hierarchical regression model showed that educational levels and insomnia were the main predictive variables for life satisfaction during the second-year postpartum. This work has important implications for clinical practice because it allows health professionals to understand the factors influencing satisfaction with life and health among fathers and to plan more effective antenatal and postnatal care.