Haag, 48, was named by Obama on Thursday. She must be confirmed by the U.S. Senate.
The U.S. attorney's office for Northern California handles federal criminal cases and civil cases concerning the U.S. government in the Bay Area and northern coastal California, from Monterey to the Oregon border.
The office is headquartered in San Francisco and has branches in Oakland and San Jose.
Haag was an assistant U.S. attorney and chief of the office's white-collar crime division from 1999 to 2003. She also was a prosecutor in the U.S. attorney's office in Los Angeles from 1989 to 1993.
Since 2003, she has worked as a defense lawyer in white-collar crime cases and as a litigator for the San Francisco law firm of Orrick, Herrington & Sutcliffe.
Haag previously worked for two other private law firms from 1987 to 1989 and 1993 to 1999.
She received her college degree from the University of California at San Diego in 1983 and her law degree from the University of California at Berkeley in 1987.
Haag was recommended for the post by U.S. Senator Barbara Boxer, D-California.
Boxer said Thursday, "She is well respected in the California legal community and will bring more than two decades of experience in handling white-collar crime cases to the U.S. attorney's office."
Haag will replace U.S. Attorney Joseph Russoniello, who was appointed to the job twice, first by President Ronald Reagan to serve from 1982 to 1990 and then by President George W. Bush to serve beginning in 2008.