Born and raised in Wilmington, Delaware, Harris moved to Honolulu to study at the University of Hawaiʻi at Mānoa, where he obtained dual undergraduate degrees in related biology fields.

Upon graduation, Harris went on to the University of California at Irvine, where he obtained his master's degree in population and environmental biology, specializing in urban ecosystems.

During his tenure, Honolulu residents voted to limit mayors to two four-year terms and thus made Harris ineligible for re-election in 2004.

He also curtailed urban sprawl by reforming the system of land use planning to preserve open spaces and agricultural districts.

Hawaiʻi Democratic leaders then backed incumbent Lieutenant Governor Mazie Hirono, a favorite of Sen. Daniel Inouye, for the nomination instead.

However, critics of Harris, including his successor Mufi Hannemann, contend that these programs came at the expense of basic city services and infrastructure.

Delegates in 1999, who included over 400 leaders from the Asia-Pacific Rim nations, voted to establish a permanent secretariat in Honolulu in Harris's honor.

Harris met Ramona Sachiko Akui while they were both working for the City and County of Honolulu, and they married in June 1989.