Tellem is married to Nancy Tellem, former entertainment and digital media president of Microsoft. They met in 1974 while both were summer interns in Washington, D.C. Nancy, a Cal junior from San Francisco, worked for Oakland congressman Ron Dellums. Arn, a sophomore at Haverford, had been hired by another California representative, Jerome Waldie, a member of the House Judiciary Committee. The couple has three sons: Michael, Matty, and Eric.