The woman claimed she traveled with him for speaking engagements, charity events and personal appearances, according to the lawsuit.
The Hall of Fame quarterback has been working as a color commentator for the Seahawks radio network, but has requested a leave of absence.
Haskell was hired in July as Moon's executive assistant at Sports 1 Marketing in Irvine, which he started in 2010.
He was forced to spend the first six years of his career in the Canadian Football League reportedly because of a league-wide bias against black quarterbacks; Moon was told he would be better off playing another position at first.
Haskell also alleges in the documents that Moon grabbed her crotch while she was sleeping on a recent business trip in Seattle. That same month, the lawsuit claims, Moon pulled off Haskell's bathing suit after slipping a drug into her drink during a trip to Mexico.
Haskell has asked for a jury trial against Moon, who now works for the Seahawks' official radio network.
Among the allegations. Haskell claims Moon would pressure her to wear revealing clothing, make inappropriate sexual remarks and advances, and force her to sleep in the same bed with him on business trips.
She said she was demoted by the firm in October after filing a complaint about Moon's behavior.
As an Eskimo, Moon won two Grey Cup MVP awards and became the first professional football player to pass for 5,000 yards in 1982.
Moon has had several public scandals with women and was sued by a Minnesota Vikings cheerleader for sexual harassment in 1995.
Moon eventually got a chance to play for the Houston Oilers in 1984 and would put up huge passing numbers in the "run and shoot" offense. The couple divorced in 2001 to end a 20-year marriage.
He appeared in nine Pro Bowls and was inducted into the Pro Football Hall of Fame in 2006.
While Haskell, 32, declined to comment on the pending lawsuit, her attorney, Diana Fitzgerald, said Haskell never went to the police with her accusations against Moon because she "was scared" and seeking to "further her career in the sports marketing industry". "She had no idea that her job duties were going to involve that kind of perverse protocol".