Greenfield graduated from Doland High School in 1994 and earned his BS in 1999 from Northern State University.
On March 30, 2020, during a late night session of the legislature Senator Kris Langer was accused by fellow State Senator Phil Jensen of being intoxicated at the Capitol, later Greenfield was also accused of being intoxicated.
[20] During the hearing Greenfield made the following statement: "I would echo the sentiments shared by Senator Langer.
Especially in these current times, there is important work to do for the people of South Dakota and I am hopeful that we can all focus moving forward.
"[21] In 2021, Greenfield announced that he was running for the office of the Commissioner of School and Public Lands.