Dan O'Connell graduated cum laude from the University of Illinois Champaign with his Juris Doctor in 1982, and was admitted to the Illinois Bar later that same year. He immediately went to work as a clerk for Judge Phillip Reinhardt in the Illinois Appellate Court. After his work with Judge Reinhard, Dan moved on to become an experienced attorney with various Chicago law firms including Gardner Carton & Douglas, specializing in civil litigation, appellate law and environmental law. In 1994 Dan shifted his focus to be closer to his own family, and moved his practice out to Kane County. He has worked as a Family Law attorney in Kane, Kendall and DuPage Counties for the last 15 years. In the last eight years, Dan has expanded his practice to include Mediation and Guardian ad Litem work for couples and children in Kane County. Dan also participates in the Kane County division of CASA (Court Appointed Special Advocate) program, which provides advocates for abused and neglected children.

Dan has has four wonderful children. He practices the martial art of Hapkido with his youngest son, and has earned a second degree black belt. Dan has been an active participant in the local Boy Scout troop, and has held various positions in the troop since 1980 including Committee Chairman, Assistant Scoutmaster, Merit Badge Counselor, and the Advancement and Training Coordinator. Dan also graduated cum laude from Catholic University in Washington, D.C. with a Bachelor of Arts: Religion & Religious Education degree in 1977.