Hatcher was born on July 10, 1933, in Michigan City, Indiana. He received a B.S. degree in business and government from Indiana University and a bachelor of law with honors in criminal law in 1956 and a J.D. from Valparaiso University School of Law in 1959. After moving to Gary, Indiana, Hatcher began practicing law in East Chicago, Indiana. In 1961, he began serving as a deputy prosecutor for Lake County, Indiana, until he was elected to Gary's City Council in 1963. He was the first and only freshman elected president of the City Council in Gary's history.
Hatcher was inaugurated mayor of Gary in 1968 and served until 1987. During his tenure as mayor, he became internationally known as a fervent and prolific civil rights spokesman. Hatcher was known for developing innovative approaches to urban problems and for being a national and international spokesman for civil rights, minorities, the poor and America's cities. He often delivered speeches alongside Martin Luther King, Robert F. Kennedy, Jesse Jackson, and other historic proponents of the civil rights movement. On April 5, 1968, he addressed President Lyndon B. Johnson, along with a collection of politicians and civil rights leaders, on the topic of the recent King assassination and pending civil unrest.