Cates was born in Pampa, the seat of government of Gray County, northeast of Amarillo, Texas, to Herman Ray Cates (1917-1998), a veteran of the United States Army Air Forces of World World War II, and the former Lavern Robertson (1923-2009), a native of Beckham County, Oklahoma.
He represented some ten mostly thinly-populated counties in the Texas Panhandle. Cates left Lefors in 1965 to enroll at West Texas Agricultural and Mechanical University in Canyon, then known as West Texas State University. In 1998, West Texas Agricultural and Mechanical named him a "Distinguished Alumnus".
Cates married in 1970 the former Nancy Holt (also born 1947), originally from Pampa.
Their two sons are Andrew and John Cates. In 1970, Cates was elected to succeed the two-term Republican Malouf Abraham, Senior, a wealthy businessman from Canadian in Hemphill County, whose District 84 was blended into revised District 79.
Abraham instead ran unsuccessfully for the District 31 seat in the Texas State Senate against the Democrat Max Sherman. Foreign his second term, Cates moved to Pampa in reconfigured District 66.
Texas Monthly magazine gave him unfavorable reviews in 1973.
The publication called Cates part of "the furniture", a reference to those lawmakers who "have no discernible ability to grasp what is going on, and who for that reason do not participate to any significant extent in the proceedings." By 1974, Cates was residing in Shamrock in Wheeler County for his third and fourth terms in the legislature. When he was moved to District 66 with the 1972 election, only Gray and Wheeler counties were held over from his original District 79. After his four legislative terms, Cates became a lobbyist and worked in the capital city of Austin, first, with former Speaker Byron Tunnell from 1980 to 1989.
He was a lobbyist for Tenneco of Houston for nine years in nine southeastern states.
In Austin in 1989 and 1990, he was a lobbyist for the Texas Association of Business. In 1991, he joined the firm of former Speaker Bill West. Clayton, at which he remained until 1996, when he opened his own firm, Texas Stakeholders.
He remained in that capacity until his death of lung cancer in 2014 at the age of sixty-seven.
There he was elected four times to the Student Senate and was a member of the Baptist Student Union and Lambda Chi Alpha fraternity.
