Astor's will left the bulk of his estate to his son, William Vincent Astor. Madeleine also received a substantial trust fund, contingent on her not remarrying (which she eventually did). His estate was one of the largest of its time.

Madeleine Astor gave birth to John Jacob Astor VI several months after her husband's death. Astor VI became a member of the prominent Astor family and inherited part of his father's estate.

The Astor family continued to play a significant role in New York society and business throughout the 20th century. Astor's descendants carried on his legacy, contributing to real estate, philanthropy, and various other endeavors. However, the power and influence of the family waned over time compared to its peak in the 19th century.

John Jacob Astor IV remains a prominent figure in history, primarily due to his wealth, social status, and tragic death on the Titanic. He is frequently referenced in books, films, and documentaries about the disaster, solidifying his place in popular culture as a symbol of wealth and privilege lost in the tragedy.