The drawing shows colorfully dressed people, including a little girl sitting on a man's shoulders, gathered on Washington's National Mall to listen to the Nobel Peace Prize winner speak.
King, whose birthday is Jan. 15, is not pictured in the image.
Famous for battling racial inequality through non-violent resistance, the minister and civil rights leader was assassinated by James Earl Ray as he stood on the balcony of a Memphis motel room on April 4, 1968. He was 39 years old when he died.
Ray died at the age of 70 while serving life in prison for the slaying.
Alveda King, his niece, was in attendance for the bill-signing ceremony.
Trump also recently signed a proclamation to honor Martin Luther King,Jr. Day, saying it is a day to mourn his loss, celebrate his legacy and pledge to fight for his dream of equality, freedom, justice and peace.
"Today we celebrate Dr. King for standing up for the self-evident truth Americans hold so dear," Trump said. "That no matter what the color of our skin, or the place of our birth, we are all created equal by God."