She was a pathologist noted for establishing cancer prevention clinics in New York. She founded two clinics: the Strang Tumor Clinic in 1932 and the Strang Cancer Prevention Clinic in 1937, which operated out of the New York Infirmary. In 1940, L'Esperance opened a second branch of the Strang Cancer Prevention Clinic at the Memorial Center for Cancer and Allied Diseases.
During her medical career, L'Esperance published her research prolifically, credited for approximately 30 articles in medical journals. Elise L'Esperance was born in Yorktown, New York to Albert Strang, a physician, and Kate Depew Strang. there in 1900. Interested in pediatrics, L'Esperance spent a year working at Babies Hospital in New York.
She then worked for two years at a private pediatric practice in Detroit, Michigan.