Sobeloff was born in Baltimore, Maryland, the son of Jacob and Mary Hilda (Kaplan) Sobeloff, who were RussianJewish immigrants.[1] Sobeloff attended public schools including Baltimore City College and the University of Maryland School of Law, where he received his Bachelor of Laws in 1915.[1] He served as a Page in the United States House of Representatives in 1910.[1] He was admitted to the Maryland Bar in 1914, was a law clerk in Baltimore the same year, and subsequently went into private practice.[1] From 1919 through 1924 he served as the assistant city solicitor for Baltimore and was appointed the deputy city solicitor for Baltimore from 1927 to 1931.[1] In 1931 he became the United States Attorney for the District of Maryland, where he served until 1934.[1] Subsequently, he was selected to be the Baltimore City Solicitor and the special counsel to Baltimore City Housing Commission.[1] He then returned to private practice from 1947 to 1952. Sobeloff served as Chairman of the Commission on the Administrative Organization of the State of Maryland from 1951 to 1952.[2] In 1952, he was appointed to the position of Chief Judge of the Maryland Court of Appeals, where he served until 1954.[1]