A Lubbock resident, Jones earned his living from farming and investments. He holds a Bachelor of Business Administration degree from Texas Tech University. He married Reta A. Jones (July 16, 1923 - March 20, 2014), shortly after the end of his service in the United States Army Air Corps during World War II. The two met in Lubbock's only bowling alley at the time. Mrs. Jones was heavily involved in Habitat for Humanity in Lubbock.
Jones's District 83 also included the outlying communities of Levelland, Denver City, Plains, Shallowater, Slaton, and Seminole, Texas. Jones drove through the district over the years in a 1995 Buick Le Sabre, passing out some 800,000 "Delwin Jones" emery boards to remind voters of pending elections. Jones often began his day of politicking meeting voters in some cafe.
At eighty-six, Jones was a candidate for renomination in the April 13, 2010, Republican runoff primary. He was defeated by Charles Perry, an accountant who ran a grass roots campaign with support of the Tea Party movement, also known as "Taxed Enough Already". Perry prevailed with 10,109 votes (57.8 percent) to Jones' 7,392 ballots (42.2 percent). Jones polled 291 more votes in the runoff than he had in the primary, but Perry's total increased by 3,633 ballots over his initial showing.
In the March 2 primary, Jones, backed by the president of the Lubbock Educators Association interest group, led the field with 7,103 ballots (37.7 percent) to Perry's 6,476 (34.4 percent). The third candidate, Zach Brady, with 5,240 votes (27.8 percent), held the key to victory in the Jones-Perry showdown. Brady, a Lubbock attorney, raised more than $250,000 and carried the backing of business interest groups, but he was eliminated from the race by his third-place showing.
Jones had expected to win another term in the legislature on the basis of his name identification and longevity, but he conceded an "undercurrent" of disgruntled taxpayers made the outcome of the race uncertain. Charles Perry then ran unopposed for the House seat in the general election held on November 2, 2010.
In the Republican primary held on May 29, 2012, Jones, at the age of eighty-eight, failed in a bid to unseat Perry. In 2014, Jones entered the special election to fill the seat in the District 28 seat in Texas State Senate vacated by Robert L. Duncan, who became chancellor of the Texas Tech University System. In this race, he again faced Charles Perry as well as several other candidates, including two other Republicans, E. M. Garza and Jodey Arrington, and Democrat Greg Wortham. On August 31, 2014, Jones was listed in critical condition from an undisclosed illness. He was admitted to Covenant Medical Center in Lubbock. Perry won the election without the need for a runoff and thereby gains seniority over other new state senators who will be elected on November 4.
Jones survived his illness. Upon his death, he will be interred at Texas State Cemetery in Austin.