Upon his honorable discharge, he enrolled at South Dakota State University where he met his wife Denise Torvik. They married in 1975. With a Bachelor of Science degree in Earth Science from the University of South Dakota, Dennis accepted a management training position with the Western Company of North America, an oil field service company, in Pearsall, TX. He also served in the Bryan, TX office as Service Supervisor and District Engineer before joining Brazos Resources, Inc., as Vice President and General Manager, and subsequently HEA Exploration, Inc. as Co-founder and President.

His second career began at Texas A&M University where he received an MBA and a Ph.D. in Business Administration. Teaching capstone courses in strategic management, primarily to MBA and Executive MBA students at Texas A&M, University of Nebraska at Omaha, and Texas State University, Dennis took great pleasure collaborating with students on team-based projects that brought insights to local and regional companies. He also enjoyed serving as faculty for study abroad experiences in Barcelona, Spain and Lima, Peru. By far, his favorite roles were father to sons Peter and Christopher and grandfather to Anna, Conor, Finn, and Andrew. Dennis spent many hours coaching his sons’ basketball, baseball, and soccer teams, and driving miles to enjoy seeing them compete on baseball fields. He was immensely proud of them and their families. Retiring from Texas State in 2021, Dennis enjoyed biking, golf, yardwork, and an occasional hand of bridge.

In addition to his wife Denise of 49 years, Dennis is survived by son Peter Smart, wife Carrie and grandchildren Anna and Finn of Overland Park, KS; and son Christopher Smart and grandsons Conor and Andrew of Round Rock, TX; brothers Paul Smart (Judy), Bill Smart, and Jack (Mary Lou) Smart; and sister Susan (Dean) Hallen. He was preceded in death by his parents, Mabel and Percy Smart; sisters, Patty McGregor and Betty Brash-Allshouse; sister- in- law Roxanne Smart; and brother-in-law Herbert Allshouse.

Funeral services were held on Saturday, October 12, 2024 at 10:00 am, at Our Lady of Wisdom University Parish, San Marcos, TX. Burial will be at a later time in Sisseton, SD. In lieu of flowers, donations would be welcome to Hope Hospice; the Dennis L. and Denise T. Smart Graduate Scholarship at the McCoy College of Business Foundation at Texas State; School Fuel San Marcos; St. Vincent de Paul Society; or a charity of your choice.