Preston Lea went to Lawrenceville in New Jersey to school. After returning to Delaware, he began at age 18 in his father's mill operating participate. This operation has been getting bigger over the years. After his father's death in 1873 was Preston Lea Vice President of the company, which now William Lea & Sons called. In 1876 he became head of the company. In addition to the activities in this company Lea worked also in other areas. Already in 1873 he was Chairman of the Trade Committee of the city of Wilmington. In 1888 he became president of the Union National Bank. He was also vice-president of an agricultural insurance company and president of the railway company Philadelphia, Baltimore & Washington Railroad and tramway Wilmington.
Preston Lea was a member of the Republican Party, which did not matter much in the 30 years following the American Civil War in Delaware. Since the 1890s this had changed. 1894 abolished the party for the first time with Joshua H. Marvil a victory in a gubernatorial election in that State. However, the party was split into two camps. A page was written by J. Edward Addicks, a millionaire from Philadelphia, supported. The other wing was in opposition to Addicks. In the gubernatorial election of 1904 the Republicans therefore competed with two candidates. Candidate of Addicks - wing was Preston Lea, of 46% of the vote against Caleb S. Penne Ville, the candidate of the Democratic Party, asserted itself. Penne Ville reached at least 41% of the votes, while Joseph H. Chandler, the other Republican candidate, came to only 2 %.
Governor of Delaware
Preston Lea took up his new post on January 17, 1905. Just a year after taking office, Addicks withdrew from politics. Result, the two republican wing in Delaware were united again. New chairman of the party in Delaware was the later U.S. Senator Thomas Coleman du Pont. In Leah's reign was the law that bound the right to vote to certain financial conditions lifted. This was particularly beneficial to the poor and the black population, which could thus choose again. It also took advantage of the Republican Party, which thereby built up a loyal voter base that assured them of a decades-long dominance in Delaware.
A border dispute with the neighboring state of New Jersey was settled. A new Education Act prescribed a compulsory education of at least three months. In the time in the United States hotly debated question of Prohibition, it was decided in Delaware for a local solution by the decision was left to the three counties. As a result of the sale of alcoholic beverages in Kent County and Sussex County was prohibited. At that time the old Chesapeake and Delaware Canal was sold to the federal government.
After the end of his tenure, Preston Lea withdrew from politics. He devoted himself to continue his still numerous business activities. He died in December 1916, and was buried in Wilmington. Preston Lea was married twice and had four children.