Adam Leijel was born in Stockholm on 8 December 1669, the second son of Henrik Lyell (1627-1710) and his wife Judit Rokes (1647-1705). Both his elder brother Henry (1665-1731) and his younger brother Baltzar (1672-1740) left Sweden and settled in England where they became wealthy directors of the English East India Company.

Adam graduated from Uppsala University in 1684, and studied in Wittenberg (1691), Leipzig (1692) and Leiden in 1693. He was enobled in Sweden on 23 April 1717 and introduced in the Stockholm House of Nobility in 1719 as nr. 1531.

On the 12 July 1713 Adam married Hedwig Lucia Lohe, daughter of the wealthy industrialist Johan Lohe (1643-1704) and his wife (1654-1731), at Biby Manor house in Söderman Lan.

In 1713 as an accessor in the College of Mines his salary was 1200 Dalers Silvermynt. (At this period , the weekly salary of a manufacturing worker in Stockholm was 1 Daler Silvermynt). In 1718 he became director of the Hallefors silverworks which his wife had inherited from her father, and where he adopted some of his cousin's metalworking techniques.

On the 4th June 1730 Adam was promoted to the position of Bergsrad (Councilor) in the College of Mines. Emanuel Swedenborg taking up the position of accessor vacated by Adam.

In later life, Adam gained the title of regional governor (1744), but died the same year.