He previously served as special assistant to the U.S. Secretary of Agriculture from 1974 to 1975, director of the New Mexico Water Resources Research Institute at NMSU, state chair of the Republican Party of New Mexico from 1977 to 1979, and United States Deputy Secretary of the Interior for Land and Resources from 1981 to 1984.

Carruthers was succeeded by Democrat Bruce King, who had previously served two non-consecutive terms as governor.

After leaving office, he served as founding president and CEO of the Cimarron Health Plan, now Molina Healthcare of New Mexico, Inc., from 1993 to 2003.

He was succeeded by John D. Floros, a food scientist and former dean of the Kansas State University College of Agriculture.

[8][9] Questioned by faculty at an on-campus meeting on his candidacy to become NMSU chancellor in 2013, Carruthers said that there was not a scientific consensus on climate change, stating "I don't know.