Commissioner Jose "Pepe" Diaz serves as the representative of District 12, which includes the cities of Doral, Hialeah, Hialeah Gardens, Medley, Sweetwater, Virginia Gardens, and a large portion of unincorporated Miami-Dade County. He was first elected as commissioner in September 2002 and re-elected for a third term in 2010.

Commissioner Diaz has served in various capacities on different committees of the County Commission.  Currently, he is the Chair of the Land Use & Development Committee and sits on the Health & Social Services and the Economic Development & Port Miami Committees. Commissioner Diaz previously served as the Vice-Chairman of the Miami-Dade Board of County Commissioners from 2009-2010. Additionally, Commissioner Diaz, who proudly served as a member of the U.S. Marine Corps, was appointed as Miami-Dade County's Military Liaison and also serves as the Chairman of the Military Affairs Board. In addition to his County duties, Commissioner Diaz also serves on the Citizens’ Crime Watch of Miami-Dade County’s Executive Committee.

Before joining the Commission, Commissioner Diaz worked to resolve the ongoing flooding issues throughout Miami-Dade County as Mayor of Sweetwater. He spent countless hours lobbying in Tallahassee and Washington, DC, and acquired the funds necessary for a Comprehensive Street Drainage Project.  Commissioner Diaz continues to work with local and state emergency management teams to avoid future flooding.  Former Governor Jeb Bush appointed Diaz to the Everglades Restoration and Eco-System Task Force, where he advises on suggested regulations that could adversely affect West Miami-Dade's water levels.

On the international level, Commissioner Diaz also serves as Chairman of the Economic Development and International Trade Department of Regulatory and Economic Resources and is an advocate for trade and forging partnerships with other nations. In March 2010, Commissioner Diaz was appointed by U.S. Trade Representative Ron Kirk to serve a four-year term on the Intergovernmental Policy Advisory Committee on Trade (IGPAC). In this capacity, Commissioner Diaz is one of several committee members chosen to advise, consult with, and make recommendations to the U.S. Trade Representative and Obama Administration from the perspective of localities. He also served as Chairman of the Jay Malina International Trade Consortium (ITC), until January 2006. During his tenure, he was instrumental in making profitable connections for businesses on behalf of Miami-Dade County with the Caribbean and Latin America.  The commissioner toured several Asian cities in 2005 - Tianjin, Hong Kong and Shanghai - and met with government officials and business organizations to promote trade partnerships; participating in a ceremony to mark a joint venture between Florida International University and Tianjin University of Commerce. The commissioner and the Asian delegation also secured a cooperative agreement for the County with Tianjin's Municipal People's Government.

Commissioner Diaz also served as the Chairman of the Board of Directors of the Miami-Dade County Sports Commission, which is charged with attracting youth, adult amateur, and professional sporting events to the county and engendering support for those events. Under the commissioner’s leadership, the Sports Commission created a local bid committee to support Miami as a host city for the 2022 FIFA World Cup and also coordinated a massive block party on Brickell Avenue to support the FIFA World cup to the United States. Last year, thanks to the Sports Commission, Miami-Dade County hosted their first WrestleMania, which generated $102.7 million in economic impact for Miami-Dade County.

The commissioner is a strong supporter of issues involving the elderly community and the military. Commissioner Diaz spear-headed "Seniors Never Alone" program, which makes sure enrolled seniors receive a call at least twice a week. The program is operated by the Switchboard of Miami, Inc. and each reassurance specialist engages seniors in conversation, and provides emergency assistance if necessary. The commissioner is also a member of the Military Affairs Committee and the Greater Miami Chambers Board of Governors. He strongly advocated for the USS Gridley, the first navy warship to be commissioned in Miami. The commissioning became a reality on Saturday, February 10, 2007.

Commissioner Jose "Pepe" Diaz is married and has three daughters. He was born in Pinar del Rio, Cuba and has lived in Sweetwater, Florida for more than 30 years. In 1979, Commissioner Diaz enlisted in the U.S. Marine Corps and was honorably discharged in December 1984.  In 1986, he began his career in public service as Chairman of the City of Sweetwater Police Retirement Trust Fund Board. For the next seven years, he served on the City of Sweetwater Commission and was ultimately elected Mayor in May 1999.

Diaz was arrested for DUI and speeding arrest in 2015 by Key West Police (who observed Diaz racing his Harley-Davidson motorcycle). A police video of the failed field sobriety test of Diaz and his subsequent refusal to take a breathalyzer test was reported by the Miami Herald and publicly released on internet media.  He was later acquitted of all charges..2.