Martin Luther King Jr. Day: Observed the third Monday in January, celebrating the life and legacy of the Civil Rights leader, as well as a commitment to service.
On August 27, 1984, President Reagan established a commission (98 Stat. 1473 ) to assist in the first observance of the Federal legal holiday honoring Martin Luther King Jr., and on January 18, 1986, President Reagan signed Proclamation 5431 (100 Stat. 4396), marking the first observance of his birthday a national holiday.
On August 23, 1994, President Clinton signed the Martin Luther King Jr. Federal Holiday and Service Act (108 Stat. 1565), expanding the mission of the holiday as a day of community service, interracial cooperation and youth anti-violence initiatives. In 1999, Title 4, United States Code, (113 Stat. 1285), was amended to add the Martin Luther King Jr. holiday to the list of days on which the flag should be displayed.
Source: MLK Day of Service, GovInfo.gov