Sleeper's education and early legal training moved across three regions of the United States: New Hampshire for her undergraduate studies, Illinois for her legal education, and Massachusetts for her admission to practice. Her path from a New England public university to a Chicago law school and then to a Massachusetts legal career reflects the regional mobility common among American lawyers trained in the decades after the 1960s.
Sleeper earned a Bachelor of Arts from the University of New Hampshire in 1986. The institution was founded in 1866 as the New Hampshire College of Agriculture and the Mechanic Arts, one of the early land-grant colleges established to serve the children of farming and laboring families. It moved from Hanover to Durham in 1893 and adopted its present name in 1923.
She continued her legal education at Northwestern University School of Law, where she received a Juris Doctor in 1989. The school traces its origins to 1859, when it began as the law department of the Old University of Chicago and became the first law school established in Chicago. It was known as the Northwestern University School of Law from 1891 until it was later renamed the Northwestern University Pritzker School of Law.
Sleeper was admitted to the bar in Massachusetts in 1989, the year she completed her law degree at Northwestern. Admission to a state bar qualifies a lawyer to practice law within that state's courts.
Her professional career includes work as a partner of S. E. Giorno, a legal practice in which she worked as a lawyer.
