Parental socialization has been studied mainly when is in process, but less is known about its long-term impact on older adults, particularly on one of the most important developmental tasks in later life: being a grandparent. Participants were 313 Spanish grandparents. The present study examined the relationship between parenting and its impacts in the long term, when the child is a grandparent. The variables examined were parenting (parental warmth and parental strictness) and grandparenting functioning (satisfaction with life, meaning of life, parent–adult child relationship quality, emotional closeness with grandchildren, and role overload). The statistical analyses were a correlation analysis and multiple linear regression analyses. A constant pattern between parenting and grandparenting functioning has been found. Warmth was positively associated with grandparenting functioning, as opposed to strictness, which did not show benefits for grandparents and even showed a significant negative relationship with an indicator of grandparenting functioning. Present findings highlight that, during the socialization years, greater parental warmth but not parental strictness might be of benefit for children at the end of their life (i.e., when they are grandparents) but also for their descendants because they have a better relationship with the two following generations (i.e., adult children and grandchildren).