Glenn started learning to play piano at about eight years of age by watching his grandmother and asking questions, and began teaching himself guitar and bass guitar about the time he started high school. Growing up around musicians, especially his dad, Jack, gave him the background in country music that has grown into a life-long pursuit.

Some of the musicians Glenn has tried to emulate over the years include his father, Jack Humphries, as well as Jim Reeves, Hank Williams Sr., Bob Wills, Willie Nelson, & George Strait (in general), Carlos Santana & Billy Gibbons (for lead guitar), Raul DiBlasio (for piano), and Bill Monroe (for mandolin). A couple of old time West Texas fiddlers served as his idols for the viola: Vivian Clark of Borden County, Texas and Ed Blakemore, of Balmorhea, both long deceased. Glenn admits he is still trying to learn the viola, and has very recently started trying to learn the pedal steel.

Graduating in 1977 from Sul Ross State University with a degree in Music, Glenn taught in several West Texas schools as a band director. At the university, Glenn played trumpet in the Lab Band, a rock and jazz oriented "stage band, and played bass guitar with a local band called "The Rio Bravo Bandits," later called "Rio Bravo Band." Glenn's first vocal efforts emerged during this period as he began learning to sing harmony to the band's lead singer, Joella Minter.

In 1979 the group disbanded (no pun intended). Then, in 1981 Glenn, now on guitar and doing lead vocals, got together with his brother Larry and began to form a new band. After a series of drummers, Peter and Chuy Matta joined the band and they began performing around West Texas under the name "The Nightriders" until May of 1987.

After a few years without a band, Glenn (now mostly on keyboards) and Larry got together with Mike Cade (Bass), John Gray (Guitar), and Charlie Sansom (Drums). They played for a couple of years using the name "Madera Valley Express," named after a well known canyon near their hometown, Balmorhea, Texas.

The band regrouped in 2001 with a new drummer, Norman Román, and Bass player Kennith Thetford. Mike switched to guitar, and the band renamed themselves "Mixed Company Band." Drummer Román left the band in the summer of 2003 and was replaced by Charlie Sansom, who had played with them before. The group performs around far West Texas, playing for dances, parties, and celebrations of all types.

Glenn sings lead vocal on some of the bands songs, including most of the Spanish songs they perform, and sings backup harmony on many others.