Esau represented the old District 18A and, later, 28A, which included all or portions of Brown, Cottonwood, Jackson, Murray and Redwood counties, changing somewhat after the 1972 legislative redistricting.

He was, along with senators Dennis Frederickson, Earl Renneke and Jim Vickerman, and representatives Aubrey Dirlam, George Mann, Henry Kalis and Wendell Erickson, one of the longest-serving legislators from southern Minnesota in the state's history.

[1] While in the legislature, Esau earned a reputation as a strong advocate for farmers, and as a leader on issues relevant to criminal justice and education.

He allied with the Conservative Caucus at a time when the legislature was still officially nonpartisan, and later identified as a Republican when party affiliation became required of candidates.

[2] His Christian service work included frequent mission trips to such places as Ukraine (his father’s birthplace), Russia, Paraguay, Peru, and the Philippines.