Theron C. Bennett was born in Pierce City, Missouri, to Vermont native George Nelson Bennett and his Missouri wife Henrietta "Hattie" Felix. It appears he was an only child to the druggist and his wife. After his schooling in Missouri, during which his mother died in the 1890s, Theron attended New Mexico College of Agriculture and Mechanic Arts (now New Mexico State University) in Las Cruces, where he obtained a degree focused on music, but possibly with some business background. While there he engaged in organizing a minstrel troupe of around twenty members with one of the professors. As of the 1900 census, Theron still listed Pierce City as his home base.

Bennett's first publication, Pickaninny Capers, came in 1902, the year he graduated. It was followed by the successful and suggestive self-published Satisfied: An Emotional Drag in 1903. This got the attention of publisher Victor Kremer of Chicago who hired him as a composer and arranger and bought Satisfied for reissue as well. It turned out to be a fortuitous move for both when in 1904 Bennett took the notorious "Buddy Bolden/Funky Butt" strain from New Orleans and incorporated into St. Louis Tickle, one of many pieces exploiting the 1904 Lewis and Clark Exposition (World's Fair) in St. Louis, Missouri. It was published using the names Barney & Seymore as the composers, in part to perhaps sound like a vaudeville act, and in part to perhaps protect the composer's identity if the use of the wicked strain backfired. Fortunately, it did not, and St. Louis Tickle, clearly a hit at the fair and often recorded since, ended up selling well for over two decades. Bennett also contributed a set of waltzes to the fair's musical mélange under his own name.

Theron wrote two fine rags over the next few years, including Sweet Pickles and Pork and Beans. He also composed an Indian intermezzo, a popular genre at that time started by Theron's friend Charles N. Daniels and his non-Indian piece Hiawatha. Lovelight was released as an instrumental, and as two songs with different lyric sets in different keys. Around 1908, as the Kremer firm began to dissipate, starting with the defection of its namesake owner, Bennett formed his own music firm which published his own works plus notable pieces like All the Grapes, California Sunshine and Melancholy Baby. His first move was to Omaha, Nebraska, in 1908 where he opened a new piano dealership. He was in Omaha for the 1910 census as a musician in a store. Within a couple of years, he had settled in Denver, Colorado, but still traveled regularly to the retailers he distributed his works, including New York, St. Louis and Omaha.

One of the more notorious episodes of his publishing career has to do with W.C. Handy's Memphis Blues. As the story goes, Bennett was visiting his Memphis representative L.Z. Phillips at Bry's Department Store. Phillips had agreed to print Memphis Blues for Handy on speculation based on the clear potential of good sales, and was waiting for the first 1000 copies for distribution in Memphis. Based on Phillips' recommendation, Bennett told Handy he would act as a distribution agent offering him national exposure, a deal hard to turn down. Phillips and Bennett were both present with Handy when the initial delivery of 1000 copies was made. When Handy came to check on sales a week or so after the delivery, Phillips and Bennett showed him a stack of nearly the full 1000 copies, noting that sales were slow, and encouraged him to simply sell the piece outright, which a confused Handy, who knew the piece had been popular, agreed to for a mere $50. What they did not tell Handy was that this was the second stack of 1000 as the first 1000 copies had sold out quickly. A few weeks later, another 10,000 copies were ordered with Bennett's imprint, and Zimmerman was offered a job as a wholesale manager. Within months, Bennett sold the piece to publisher Joe Morris for a rather large amount. To make matters worse, Bennett's frequent lyricist George Norton was hired by Morris to add words to a song version of Memphis Blues which were only fair at best, and which Handy objected to. The whole episode compelled Handy to form his own music company, Handy and Pace, which was successful on its own merits for many years.

Bennett pulled a similar number on Ernie Burnett's Melancholy, first getting Burnett to agree to have Norton replace the lyrics that Burnett's wife Maybelle Watson had penned, and then altering the title to Melancholy Baby after having bought it outright. The piece did very well for the publisher throughout most of his remaining life. During this period Bennett also started a chain of music stores with his profits from the sales, primarily offering sheet music and records. He had outlets in Denver, New York City, Omaha, Chicago, St. Louis and Memphis.

Bennett continued to write and publish some of his own works as well. Chills and Fevers was a good seller for his company. In Denver, Theron was listed in the mid to late-1910s as not only a publisher but as the proprietor of the Dutch Mill Café (a descendant of which is still in operation today), which was also a music store. It was evidently one of the great meeting places of Denver musicians and artists. In 1917 he published the song Around Her Neck She Wore a Yellow Ribbon, which is the source of the tradition for yellow ribbons in honor of those who have gone to war, and possibly the later song Tie a Yellow Ribbon 'Round the Old Oak Tree. The authorship of this song remains disputed to this day, but it was likely an older folk melody that Bennett simply adapted and arranged. When it was later included in the John Wayne film She Wore a Yellow Ribbon, Leroy Parker and M. Ottner received composition credit.

Theron's 1918 draft record described him as being short with a medium build, and black hair with brown eyes. It also indicated that his father had now retired to Florida. This and other existing records indicate that he had likely never married. In the 1920 census Bennett was listed as the manager of a department store, likely the sheet music department within the store. There is a mention of him in The Music Trade Review of December 24, 1921:

Theron Bennett (standing left) and friends in front
of the Dutch Mill Café in Denver c.1920

After a decade or so in Denver, Bennett followed the crowds down to Southern California in 1922, and remained there for the rest of his life. It wasn't long before he formed a jazz band primarily composed of band students from the University of Southern California (USC) as well as his own society orchestra. His group was among the first in Southern California to play live on the new medium of radio before the end of 1922. As referenced in The Music Trade Review of April 14, 1923:

Theron also conducted the Packard Six Orchestra (sponsored by the automobile company of the same name), and still appeared with his Dutch Mill Orchestra, both frequently heard on KFI. In the mid-1920s KFI, a clear channel station, could often be heard as far off as the East Coast, reflected in the radio listings of papers like The Washington Post and The Bridgeport [Connecticut] Telegram.

In the mid-1920s Bennett opened his own school of popular music, dance music and jazz piano at 3290 W. Pico Boulevard in Los Angeles, advertising it heavily in 1926. He also served as the president of the California organization of former New Mexico students for his alma mater. As of the 1930 enumeration, Theron was listed as a music teacher with a house mate, Austen Peerly, a local gardener and landscaper 30 years younger than the composer. As the Great Depression settled in, Bennett's businesses all folded and he lost virtually all of his assets. Theron Bennett died nearly destitute in 1937 at age 57 after a prolonged illness. The official obituary in the Los Angeles Times incorrectly listed Melancholy Baby and Memphis Blues as being among his compositions, which further exacerbated that lingering issue. The New York Times got it correct, however. He left behind a fair body of pieces that he either composed or published, and some of them are pieces that are still well remembered today as important works of the ragtime era. Bennett was honored at one of the earliest ragtime festivals organized by Bob Darch in Pierce City in September 1961.