[2] In 1955, Shawnee Mission Hospital was founded when local leaders, medical professionals from the Johnson County Medical Society, and members of the New Haven Seventh-day Adventist Church in Overland Park, Kansas, came together to address the developing population's healthcare needs in Johnson County.

In 1972, ownership of the hospital was transferred to the Seventh-day Adventist Church, and it was placed under the direction of the Central (now Mid-America) Union Conference.

[4][5] On November 1, 2002, Shawnee Mission Medical Center split from Saint Luke's and became a part of the Altamonte Springs, Florida-based Adventist Health System.

A 24-bed Level III Neonatal Intensive Care Unit (NICU) with private, single-family rooms was included in the expansion.

[9][10] In early April 2013, construction began on the ground floor of the Santa Fe medical office building for a $5.5 million outpatient cancer center.

[14][15] On June 22, 2015, construction workers began to renovate the cafeteria at Shawnee Mission Medical Center for $25 million, it was expected to be completed in the fall of 2016.

[27] In early November 2017, Shawnee Mission Health became the 17th member of MD Anderson Cancer Network.

[34] In early 2022, AdventHealth Shawnee Mission began a two phase renovation project to update the original patient tower.

[42][43] The new AdventHealth Cancer Center Shawnee Mission will cost $76.5 million to build and it will double the number of patients being treated.

[37][38][44] On July 18, demolition of the two-story parking garage began and the official groundbreaking of the cancer center was in October.

[47] In late November 2017, Shawnee Mission Medical Center received the HIMSS Analytics Stage 7 Award for its electronic health record.