Irmgard Lenel was born in Manheim, Germany, on July 1, 1901, to the manufacturer Richard Lenel and his wife, Emilie (nee Maas). Lenel was raised in Manheim, where she attended the Manheim School for Social Work, and after completing her training there she worked as a private secretary for Professor S.P. Altmann. After that, she spent a year attending The London School of Economics to improve her command of the English language. Upon her return to Germany in the mid-1920s, she spent three years as a magazine editor and then six working as a secretary for the publishing firm Ullstein Verlag.
Lenel emigrated to the United States in 1937 and lived in New York City until 1941, when she moved to Santa Monica, California. While living in California, she held a number of secretarial and stenographer positions. She was naturalized in 1941, and worked at the Veterans Administration for six years. In 1947 she was let go on suspicion of disloyalty to the United States. She appealed her dismissal and was found to have been unjustly terminated. After her hearing, she became active in the defense of others charged with performing un-American activities. Lenel never married, and had no children. She passed away in Santa Monica in November 2001.