Judge Osler is a Seattle native. She did her undergraduate work at the University of Washington, graduating with a B.A. in Society and Justice. She received her law degree from the University of Puget Sound School of Law in 1991.

Judge Osler has worked for the Clark County Prosecutor's Office since January of 1992. During that time, she specialized in the Major Crimes Unit prosecuting murderers, rapists and robbers. Between 1995 and 1998 she prosecuted child abusers. She has argued cases in both the Washington State Supreme Court and Court of Appeals. She was also named Deputy Prosecutor of the Year by the Law Enforcement Community of Clark County.