David A. Grennan



  • Creighton University School of Law (J.D., 2009)
  • University of Notre Dame (B.A., 2005)


About David

Dave, a native of Omaha, Nebraska, earned his Bachelor's Degree from the University of Notre Dame's business school in May 2005. Dave returned to Omaha and received his juris doctorate from the Creighton University School of Law in May 2009. While a student at the Creighton University School of Law, Dave was a member of the Moot Court Board, a member of the Client Counseling and Negotiations Board, and a CALI Award recipient. 

Dave is a member of the South Dakota Bar, admitted in 2009. Following graduation from law school, Dave practiced with a Sioux Falls law firm for approximately three years before joining May & Johnson, P.C. in July 2012. 

Dave has developed a comprehensive civil litigation practice, with a focus on employment law and insurance defense.  Dave also handles family law issues, including divorce and custody matters.  Dave has successfully advocated for his clients in both state and federal court, and through trials, hearings, depositions, and mediations.


  • South Dakota; U.S. District Court, District of South Dakota


  • South Dakota Defense Lawyers Association
  • Defense Research Institute
  •  Second Judicial Circuit Bar Association
  •  State Bar of South Dakota

Areas of Practice

Family Law

  • Divorce
  • Custody 

Insurance Defense

  • Liability Defense
  • Subrogation

 Labor & Employment Law

  • Discrimination
  • Harassment
  • Unlawful Termination
  • Employer / Employee Rights


  • Insurance Defense
  • Employment