After returning to the United States to avoid the instability brought on by World War II, she directed the nursing refresher program at Yale New Haven Hospital in 1942.

She built and continually revised the curriculum, hired faculty (the first of whom was Josephine Dolan), and worked with hospitals to establish clinical experiences for students.

The school graduated its first bachelor's degree cohort in 1947 and established a Sigma Theta Tau honor society chapter in 1955.

[2] After retirement, Widmer remained active in the national nursing community as well as local organizations near her home in Storrs.

[1] She served as president of the Mansfield Historical Society, the Windham Hospital Auxiliary, and the Connecticut Nurses Association.

[2] Opened in 2012,[5] the Carolyn Ladd Widmer Wing of Storrs Hall (site of the nursing school) was named in her honor.