The museum was built on the grounds of Oak Hall, the home of Kansas City Star publisher William Rockhill Nelson (1841-1915). When he died in 1915, his will provided that upon the deaths of his wife and daughter, the proceeds of his entire estate would go to purchasing artwork for public enjoyment.
In 1911, former schoolteacher Mary McAfee Atkins (1836-1911), widow of real estate speculator James Burris Atkins, bequeathed $300,000 to establish an art museum. Through sound management of the estate, this amount grew to $700,000 by 1927. Original plans called for two art museums based on the separate bequests. However, trustees of the two estates decided to combine the two bequests along with smaller bequests from others to make a single major art institution.