|Alma mater||Baylor University|
|Occupation||Petroleum industry executive|
|Known for||Along with his mother and brother, he is the beneficial owner of 16% of Koch Industries|
Preston is the son of E. Pierce Marshall and Elaine Tettemer Marshall and the grandson of J. Howard Marshall, who owned a 16% interest in Koch Industries and was married to Anna Nicole Smith during the last year of his life. His is the nephew of J. Howard Marshall III, who was left out of his father's will and testament.
As a trustee and a beneficiary of various family trusts, he was also a defendant in a case, decided in 2014, regarding gift tax due from an indirect gift of shares of Koch Industries by his grandfather to these trusts in 1995.
In 2017, Preston was sued over a management dispute and allegations of delaying a $1 million donation to Tulane University from a family trust that he jointly controls with his brother, E. Pierce Marshall, Jr.