Michael Dean Greff

Michael Dean Greff, age 78, of Custer, South Dakota, passed away on November 5, 2026, surrounded by his wife and family. He was born September 27, 1948, in Dickinson, North Dakota, the son of Michael and Gladys (Uhler) Greff.

While pursuing a degree in accounting, Mike enlisted in the U.S. Navy after being drafted and served on the USS Coral Sea.

After his honorable discharge, he eventually started working in the oilfield with his brother-in-law Joe Hurt. Mike had a successful career spanning almost 40 years working offshore Belize, North Dakota and Wyoming.

In 1979 he met Lee Ann and in 1980 they were married in an Episcoal church after the Catholic Church burned to the ground, a fact Mike never missed joking about. Mike and Lee Ann had 5 children in Williston, North Dakota before moving to Riverton, Wyoming.

Mike was a devout Catholic and his faith was a core aspect of his life. Whether it was in North Dakota, Wyoming or South Dakota, Mike always enjoyed volunteering and participating with the Knights of Columbus and the Catholic Church.

Mike worked hard; anyone who tried to chop wood with him was unlikely to keep up, and he always needed a project to keep him busy. He loved being in the mountains and was especially proud of the garage he built with his sawmill.

Once he had grandkids, his biggest joy in life was taking them on gator rides, followed by a glass of wine.

His sense of humor was endless, though sometimes not always appreciated… Even while undergoing chemo he tried to bring a smile to every person he met.

He is survived by his wife, Lee Ann (Gannaway) Greff of Custer; his daughters Amy, Nicole, and Maria; his son John; brothers Leo and David; sisters Brenda, Paulette, Pandora, Donna, and Cindy; and grandchildren Carlee, James, Julia, Greta, Madeline, Michael, Noelle, Evangeline, Wyatt, Natalie, Laura, Katie . He was preceded in death by his parents; brothers Dennis, Paul, and Daniel; son Steven; grandson Adam; and other children and grandchildren who died before birth.

A vigil will be held Sunday November 8th at 5pm, with a funeral Mass at 10:00 a.m. on Monday, November 9, 2026, at St. John the Baptist Catholic Church in Custer, followed by burial.

In lieu of flowers, memorials may be made to the St. John the Baptist Building Fund or to a charity of choice.