Gordon Lee Beneke was born in Fort Worth, Texas, on February 12, 1914. He started on saxophone at nine, moving from soprano to alto and finally to tenor, and played in regional bands in Texas and Oklahoma before his first professional job with the Ben Young orchestra in 1935. In 1938 Gene Krupa, who had just left Benny Goodman and was putting together a band of his own, heard Young's group, could not use Beneke because his saxophone section was already full, and passed the name on to Glenn Miller, who was assembling an orchestra in New York. Beneke joined Miller that year at a reported salary of $52.50 a week.

Miller made him his main tenor soloist, and Beneke played all but a handful of the tenor solos on the band's records and appearances until it disbanded in 1942. On "In the Mood," recorded August 1, 1939, he trades two-bar tenor phrases with his section-mate Al Klink, and the two repeat the exchange on "A String of Pearls" in 1941. He was also the band's male vocalist on its dance and novelty hits. "Chattanooga Choo Choo," recorded in Hollywood on May 7, 1941 for the film Sun Valley Serenade with Paula Kelly and the Modernaires, became the first record certified gold, presented February 10, 1942. "(I've Got a Gal in) Kalamazoo" followed in May 1942 for Orchestra Wives, with Marion Hutton and the Modernaires, and he is credited on "Juke Box Saturday Night" the same year. His New York Times obituary says the two films helped lift him to the top of the Down Beat and Metronome polls. In January 1941 he was one of the players chosen for the Metronome All-Star band that recorded "One O'Clock Jump" and "Bugle Call Rag," alongside Goodman, Coleman Hawkins, Benny Carter, Harry James, Tommy Dorsey, Count Basie, Charlie Christian and Buddy Rich, and he takes a short solo on "Bugle Call Rag."

When Miller broke up the band in 1942 to join the Army Air Forces, Beneke worked briefly with Horace Heidt and then joined the Navy, where he led service dance bands, one of them in Oklahoma. He never played in Miller's Air Force orchestra. Miller disappeared on a flight to France on December 15, 1944. In 1946 Miller's widow and estate authorized a new Glenn Miller Orchestra and put Beneke in charge of it. It opened at the Capitol Theatre in New York on January 24, 1946 for a three-week engagement, carried a large string section modelled on Miller's Air Force band, and had Henry Mancini as its pianist and one of its arrangers, with Norman Leyden also arranging. It recorded for RCA Victor and was an immediate commercial success. "Give Me Five Minutes More," recorded May 27, 1946, and "Hey! Ba-Ba-Re-Bop," a cover of a Lionel Hampton hit that reached No. 4 on the pop chart, both made Billboard's year-end list for 1946. "The Anniversary Song" made the 1947 list, "A Gal in Calico" reached No. 6 in 1947, and "St. Louis Blues March" made the 1948 year-end list. In December 1947 the band drew a record crowd of 6,750 dancers to the Hollywood Palladium.

The estate and its bandleader wanted different things, and the disagreement ended the arrangement. Beneke believed Miller had promised him a band of his own and wanted the orchestra to develop an identity beyond the prewar sound. The estate wanted Miller's songs played in Miller's style, built on the reed-centered sound Miller had made his trademark, and Beneke's obituary in the New York Times says the band's manager and producer insisted that the music stay faithful to Miller's prewar work with no experiments. The string section was dropped in 1949, and at the end of 1950 Beneke left the orchestra and parted company with the estate. He went on as "Tex Beneke and His Orchestra: Playing the Music Made Famous by Glenn Miller." The break was acrimonious at the time, but by 2017 the Miller estate listed him as a former leader of the Glenn Miller Orchestra and the orchestra's website had a page acknowledging his role.

The 1950s were leaner. Beneke recorded for smaller labels such as Coral and competed with other Miller alumni and imitators, among them Ray Anthony, Jerry Gray and Ralph Flanagan. The singer Eydie Gormé worked with his band in 1950, and the drummer Mel Lewis and Bob Brookmeyer, then still a pianist, both passed through it in the early 1950s on their way to jazz careers. In 1958 he reunited with Ray Eberle, Paula Kelly and the Modernaires for the Coral LP Reunion in Hi-Fi, billed to the Former Glenn Miller Singers, which re-created Miller hits in high fidelity, and in 1965 he made Christmas Serenade in the Glenn Miller Style for Columbia. In 1972 he re-recorded his Miller vocals for Time-Life Records' The Swing Era series, produced and conducted by Billy May. Through the 1970s and 1980s he led a band that mixed the old repertoire with newer material, played Disneyland and Knott's Berry Farm, and appeared on talk shows, sometimes in tenor duets with his old section-mate Al Klink on The Tonight Show. He also toured for a time with Helen O'Connell and Bob Eberly, the former Jimmy Dorsey vocalists.

A stroke in the mid-1990s forced him to give up the saxophone, although he kept conducting and singing. He received a star on the Hollywood Walk of Fame in 1991, and in 1998 he launched a tour honoring the Army Air Force Band. Beneke passed away on May 30, 2000, of respiratory failure at a nursing home in Costa Mesa, California, at the age of 86. He is buried at Greenwood Memorial Park in Fort Worth.

Beneke was a swing-era tenor saxophonist and a pop and novelty singer, and the two halves of his reputation point in different directions. As an instrumentalist he was a tenor soloist working inside the Miller arrangements, in short features and section exchanges and not long improvisations. His vocals were the commercial side: easygoing Southern phrasing, often in call and response with the Modernaires, on songs such as "Chattanooga Choo Choo," "Kalamazoo" and the postwar "Five Minutes More," most of them light dance-band or novelty material and not jazz. Jazz listeners more often meet him as a name on Miller records than as a leader. The jazz side is real and documented all the same: the Metronome All-Star date, the tenor exchanges with Al Klink on "In the Mood" and "A String of Pearls," and the judgment of the critic Will Friedwald, who counts him among the major blues singers who sang with the big bands of the early 1940s and singles out his reading of Mary Lou Williams's "What's Your Story, Morning Glory?" with the Miller band. His 1946 cover of Lionel Hampton's "Hey! Ba-Ba-Re-Bop" brought a rhythm and blues number into the same dance-band format. AllMusic files his work under Big Band, Swing and Sweet Bands.