Hooker was born in Poultney, Vermont, reports have differed on the date. He graduated from Middlebury College and moved to Milwaukee in 1856. Later, he married Sarah P. Harris. They had three children before she died. In 1872, he married Julia Ashley. They also had three children. He would later become General Counsel of Northwestern Mutual Life Insurance Company. Hooker died of heart disease on March 6, 1888 in Jacksonville, Florida. He was buried at Forest Home Cemetery.

Hooker was City Attorney of Milwaukee from 1867 to 1870. He was elected mayor in 1872 and served one term. Hooker was a Democrat.

• David G. Hooker at Find a Grave  
• The Political Graveyard