He has worked as musician, producer, arranger and songwriter with Nokie Edwards, Tom Brumley, James Blackwood, Ann-Margret, Engelbert Humperdinck, Trini Lopez, and Ronnie Dawson.
He also studied classical music as a child, and he was part of the first group of students admitted by audition to Southern Methodist University's (SMU) newly created Piano Preparatory Department.
He arranged for the band to play in theaters throughout Texas and Oklahoma, and brought his experience as a rock bassist to their musical style.
[15] Also in 1997, the Doughboys joined the Southern Methodist University Mustang Band[16] and worked on a recording entitled The High Road on the Hilltop.
[8] Greenhaw wrote three of the songs that were recorded, "High Road", "Texas Women" and "Hangin' 'Round Deep Ellum".
[17] The 2005 album 20th Century Gospel: From Hymns to Blackwood Brothers Tribute to Christian Country, included contributions from Greenhaw and the Light Crust Doughboys, as well as The Jordanaires and Nokie Edwards.
"[18] In 2006, for the Diamond Anniversary of the Light Crust Doughboys, America Sejung Corporation (ASC) were commissioned to produce a limited edition series of seven fretted musical instruments.