Experienced, Esteemed And Ready To Defend

Headshot of D. Sonny Walter

D. Sonny Walter

Practice Areas

  • Criminal Defense
  • Drug Charges Defense
  • Assault Charges Defense
  • Theft Charges Defense
  • Sex Crimes Defense


I was born and raised in Freeman, SD. I graduated from Freeman High School in 1979. After that, I attended and graduated from the University of South Dakota in 1985 with a Bachelor of Science degree.

I then attended and graduated from the University South Dakota School of Law in 1989. I was licensed and admitted to practice law by the Supreme Court of South Dakota in October of the same year. From 1989 to 1996, I worked for the Minnehaha County Public Defender's Office in Sioux Falls, SD. I worked with and learned from a great group of criminal defense attorneys at that office.

In 1996, I was admitted to practice in the United States District Court for the District of South Dakota. I have tried many misdemeanor and felony cases throughout my career across the state. I held the record with the Minnehaha County Public Defender's Office for the most jury trial wins until 2006. I won every misdemeanor case I tried for 14 years. I have also won most of the felony cases I have tried.

Since 1996, I have owned and operated my private practice. I have focused almost exclusively on criminal defense, handling a wide variety of crimal cases all over the state.

From 1999 to 2017, I was contracted the governor of the state of South Dakota to assist inmates in the penitentiaries in Sioux Falls, Springfield, and Yankton on various matters such as appeals, habeas corpus, parole issues, prison conditions, sentence modifications, and more.

I taught constitutional law and legal research at two local colleges in Sioux Falls.


  • University of South Dakota School of Law, Vermillion, South Dakota
    • J.D. - 1989
  • University of South Dakota
    • B.S., Bachelor of Science - 1985

Bar Admissions

  • South Dakota, 1989
  • U.S. Supreme Court, 2017
  • U.S. District Court District of South Dakota, 1996

Case Results

  • State v. Pharis, Brookings County. , Aggravated assault charge reduced to disorderly conduct.
  • State v. Jones., Won appeal to South Dakota Supreme making new law which resulted in law enforcement being required to get a search warrant before placing a pole video camera to surveil someone’s residence.
  • State v. Jackson, Davison County., Got 164 pounds of marijuana evidence suppressed due to illegal search which resulted in case being dismissed.
  • Stave v. Holforty, Beadle county. , 5 minute not guilty verdict on rape 2nd degree case.
  • State v. Vomacka, Brookings county. , Not guilty verdict in Rape in the first degree case and sexual contact case.
  • State v. Lololong, Minnehaha County. , Case dismissed by proving someone impersonated my client and proving client was not in town at time crime committed.
  • Stave v. Leetz, Minnehaha County., Possession of controlled substance reduced to misdemeanor and suspended imposition of sentence granted. All based on Motion to suppress evidence for illegal search.
  • State v. Johnson, Minnehaha County. , Cased dismissed based upon illegal search by law enforcement whom I proved lied about getting permission to enter home.
  • State v. Baier, Minnehaha County. , Got Aggravated assault case dismissed.
  • State v. Vosberg, Hamlin County. , Not guilty verdict in attempted murder case.
  • State v. Hale., Won appeal to South Dakota Supreme court on plea agreement.
  • State v. Beach, Lyman County., 10 day jail sentence for client caught with 50lbs of marijuana.
  • State v. Becking, Codington County., Got aggravated assault charge dismissed before trial.
  • State v. Easterlin, Davison County., Suspended imposition of sentence on case where client caught with 10lbs of marijuana.
  • State v. Fallon, Davison county., Felony Drug Case dismissed after winning motion to suppress evidence based upon illegal stop.
  • State v. Smith, Turner County., Case dismissed after winning motion to suppress evidence based upon illegal entry by law enforcement.
  • State v. Hinrichs, Minnehaha County. , Got Burglary case dismissed by proving alleged victim lied.

Professional Associations

  • South Dakota Association Criminal Defense Lawyers, 2013 to Present

Representative Cases

  • State v. Jones, 2017 SD 59, South Dakota
  • State v. Hale, 2018 SD 9, South Dakota

Past Positions​

  • Minnehaha County Public Defenders Office, Attorney, 1989 to 1996