Preston Lea was educated at Lawrenceville, New Jersey, and began his career under his father's mentorship. After his father's passing, he assumed leadership roles within the family business, eventually becoming president of William Lea & Sons. Lea's professional expertise spans multiple leadership positions in banking, insurance, and transportation sectors, including the presidency of the Wilmington Board of Trade and Union National Bank. His governance as governor saw significant legislative achievements, such as the outlawing of the state pillory and the resolution of a boundary dispute with New Jersey.

Preston Lea's political identity is marked by a blend of traditional values and progressive reforms, underscored by his leadership in both industrial and political spheres. His administration's outlawing of the state pillory and implementation of school attendance laws reveal a surprising progressive streak in criminal justice and education. Meanwhile, his support for local option legislation on alcohol sales prohibition and the sale of the Chesapeake and Delaware Canal to the Federal Government illustrate a calculated approach to regional economic interests. Lea's involvement with the Union Republicans faction highlights his ideological agility, navigating between established Republican leaders and emerging influences.