The hospital provides comprehensive pediatric specialties and subspecialties to infants, children, teens, and young adults aged 0–21[3][4][5] throughout Baltimore and the wider United States.

The new hospital was set to be named after Baltimore resident Harriet Lane Johnston after she donated $400,000 in 1903 to establish the home as a memorial to her two sons who had died in childhood.

[10] Eventually treating over 60,000 children a year, the Harriet Lane Home became a pioneer treatment, teaching, and research clinic, and the first to have subspecialties in pediatrics as created by Edwards A.

From 1930 to 1963 Helen Taussig, who helped to develop the blue baby operation, headed the pediatric cardiac clinic.

Lawson Wilkins established an endocrine clinic that developed procedures used universally to treat children with certain glandular disorders, including dwarfism.

John E. Bordley and William G. Hardy made strides in detecting hearing impairments in very young children.

[14] In May 2012, the Johns Hopkins Hospital opened two new towers as part of a major campus redevelopment effort.

[20][21][22] The hospital has an American Academy of Pediatrics verified level IV neonatal intensive care unit[23] that has a capacity of 45 bassinets.