Greg Harrison knows how to jazz things up. By day, with a doctorate from George Washington University in engineering, he is a forensic engineer and appears as an expert witness in legal cases involving product liability. By night, Harrison, on clarinet, is the leader of the Greg Harrison Jazz Band with fellow musicians Jay Miles on acoustic bass and Rick Rowe on guitar. They bring their lively 1920s, ’30s and ‘40s-era swing and New Orleans jazz to the Kennedy Center, restaurants, clubs and private gigs, and have recorded several CDs.

Harrison, who lives in Gaithersburg, is joined by native Washingtonian and Olney resident Rick Rowe who lends his talents on an archtop, hollow body Gibson ES-175 1970-vintage electric guitar. After more than three decades in the plastics distribution industry and performing, Rowe is now a fulltime professional musician.

Frederick resident Jay Miles has been part of Harrison’s ensemble for 25 years. He is a fulltime professional musician with a part-time day job as a records manager at the National Institutes of Health. He has been playing acoustic bass for 26 years, tuba for 38 years and electric bass for 39 years.

The moniker ‘Renaissance man’ might be attributed to Harrison who, in addition to his engineering and musical talents, became a Montgomery County volunteer firefighter when he was 16, which he continued through the 1990s; he also has a fourth degree black belt in Tae Kwon Do. His storied accomplishments weave a tale of persistence from his 30-year off-and-on endeavors to complete college undergraduate and advanced degrees, to his determination to master the clarinet that began when he was in junior high school and saw the late, legendary New Orleans jazz clarinetist Pete Fountain on “The Lawrence Welk Show.” Fountain became Harrison’s mentor.

“I fell in love with that music and his sound of the clarinet,” Harrison said. “My father simply gave me permission to go to work and buy one. It cost me $123.50, earned cutting grass.” Harrison said he “tried really hard to learn,” paid for his clarinet lessons and “had to ride my bike for miles to them, but everyone around me, especially the dog, begged me to quit and when the band director told me to give it up too, that was it … I knew I was musically challenged.”

A decade later in the 1970s, a serendipitous business trip to Las Vegas put him face-to-face with a marquee announcing Pete Fountain at the Tropicana. “I decided to go, wondering if it would be a turn-on like it was when I was 12 years old. It was even better. I met Pete backstage and we became friends,” Harrison said. He bought a clarinet and took lessons for 17 years with Sidney Forrest, the late renowned classical clarinet teacher from Baltimore’s Peabody Conservatory of Music who lived in Kensington.

Harrison maintained his friendship with Fountain, keeping him abreast of his accomplishments with the clarinet and traveling to see him. “When I could save up and afford a plane ticket, he greeted me every time and asked me to play some notes for him. I could never play anything nice if he was in the room, of course. He just smiled and said ‘keep tootin’.’”

Years later, Harrison received a package and “was stunned to see that it was a gold-keyed special Pete Fountain clarinet. I about died.” The gift encouraged Harrison to study even harder. He began copying notes from Fountain’s records and after decades of dedication, he said Fountain invited him to join him on the “famed stage of the Hilton Jazz Club. … It was totally intimidating. … He just laughed at me and the curtain went up.”

Harrison said that as Fountain aged and suffered some health setbacks, he would visit him and stand by in case Fountain needed to leave the stage. “One night when we were both performing on stage, he slowly turned before the lights were going dim and said, ‘Son, it is all yours.’ He literally walked off stage for a rest. Well, you either pee in your pants and crash and catch on fire or come out of your shoes,” Harrison explained, meaning that you rise above like never before. “I walked on air after that one. Pete was happy with my clarinet performance and he said I had finally made it. … Nice, but I didn’t think so and kept practicing.”

Harrison said he copied Fountain the best he could. “Pete had a clarinet sound to die for and put his soul through the clarinet. Others played a million notes real fast never discovering the one genius note that Pete would latch onto and just hold over the chord changes bending and shaping it all the while. There is only one Pete and there will never be another. I simply do my best to try and play with a good clarinet sound and perform his style hoping I remind the listener of Pete Fountain and maybe bring back a memory or influence a younger player to gravitate towards him.” In August, Harrison attended Fountain’s funeral in New Orleans and performed in the processional.

Harrison’s clarinet is a Buffet Prestige. He said he might change to an “antique 1960 Selmer larger bore clarinet to capture Pete’s 1950s sound.” Harrison’s favorite tunes include “Ain’t Misbehavin’,” “Tin Roof Blues,” “You Are My Sunshine,” “Bill Bailey,” “Love Me or Leave Me,” “The Preacher,” and “Blue Skies.” He recently ended a set brilliantly performing one of Fountain’s signature songs, “Shine.” “The song made Louis Armstrong household-famous,” Harrison said. “I was on it front and back. … I was out of my shoes. … It’s the fact that I lost myself and as an engineer, that’s not easy to do.”

The Greg Harrison Jazz Band performs Tuesdays, 6 to 9 p.m. at Mon Ami Gabi, 7239 Woodmont Ave., Bethesda.