Born in Evanston, Illinois. took classes during high school at the Corcoran School of Art. In 1931 Blakeslee moved to Chester Springs, Pennsylvania to study at the Pennsylvania Academy of the Fine Arts. In 1936 married Francis Speight. In 1961 Sarah Blakeslee and husband Francis Speight relocated from Pennsylvania to Greenville, North Carolina where he took on a teaching position at East Carolina University. Sarah continued to paint and teach during the 1960’s and 1970’s at various art centers in Greenville, Kinston, Washington and Rocky Mount, North Carolina. The artist returned to Pennsylvania following her husband’s death and lived near her children until her death in 2005.