Updated 10:18 p.m. ET

In an unexpected and abrupt announcement, Bill Daley, the former White House chief of staff and longtime Democratic political operative, is ending his bid for the Democratic nomination for Illinois governor.

William Daley. (Photo by Alex Wong/Getty Images for Meet the Press)

Daley served as a chief of staff for President Obama and previously served as commerce secretary, chairman for Al Gore's 2000 presidential campaign and is the son and brother of two former Chicago mayors. His decision to drop out of the race comes only four months after he announced plans to challenge Democratic Gov. Pat Quinn.