Thomas Francis "Tommy" Dorsey, Jr. (November 19, 1905 - November 26, 1956) was an American jazz trombonist, trumpeter, composer, andbandleader of the Big Band era. He was known as "The Sentimental Gentleman of Swing", because of his smooth-toned trombone playing. Although he was not known for being a notable soloist, his technical skill on the trombone gave him renown amongst other musicians. He was the younger brother of bandleader Jimmy Dorsey. After Dorsey broke with his brother in the mid-1930s, he led an extremely popular and highly successful band from the late 1930s into the 1950s.
Thomas Francis Dorsey, Jr., was born in Shenandoah, Pennsylvania, the second of four children born to Thomas Francis Dorsey, Sr., and Theresa (née Langton) Dorsey. He and Jimmy, his older brother by slightly less than two years, would become famous as the "Dorsey Brothers". The two younger siblings were Mary and Edward (who died young). Tommy Dorsey initially studied the trumpet with his father, only to later switch to the trombone.
His Father, Thomas F. Dorsey, Sr. died July 13, 1942. Thomas Sr was born in Shenandoah, PA and was a bandleader himself.
At age 15, Jimmy recommended Tommy as the replacement for Russ Morgan in the 1920s territory band "The Scranton Sirens." Tommy and Jimmy worked in several bands, including those of Tal Henry, Rudy Vallee, Vincent Lopez, Nathaniel Shilkret. In 1923, Dorsey followed his brother Jimmy to Detroit to play in Jean Goldkette's band and later returned to New York in 1925 to play with the California Ramblers. In 1927 he joined Paul Whiteman. In 1929, the Dorsey Brothers had their first hit with "Coquette" for OKeh records.
In 1934, the Dorsey Brothers band signed with Decca records, having a hit with "I Believe In Miracles". Future bandleader Glenn Miller was a member of the Dorsey Brothers Orchestra in 1934 and 1935, composing "Annie's Cousin Fanny", "Tomorrow's Another Day", "Harlem Chapel Chimes", and "Dese Dem Dose", all recorded for Decca, for the band. Ongoing acrimony between the brothers, however, led to Tommy Dorsey's walking out to form his own band in 1935, just as the orchestra was having a hit with "Every Little Moment."  Dorsey's orchestra was known primarily for its renderings of ballads at dance tempos, frequently with singers such as Jack Leonard and Frank Sinatra
Tommy Dorsey's first band was formed out of the remains of the Joe Haymes band, and so began Dorsey's long-running practice of raiding other bands for talent. If he admired a vocalist, musician, or arranger, he would think nothing of taking over their contracts and careers. Dorsey had a reputation for being a perfectionist. He was volatile and also known to hire and fire (and sometimes rehire) musicians based on his mood. The new band was popular from almost the moment it signed with RCA Victor with "On Treasure Island", the first of four hits for the new band in 1935. After his 1935 recording however, Dorsey's manager cut the "hot jazz" that Dorsey had mixed with his own lyrical style and instead had Dorsey play pop and vocal tunes. Dorsey would keep his Clambake Seven as a Dixieland group that played during performances, too. The Dorsey band had a national radio presence in 1936, first from Dallas and then from Los Angeles. Tommy Dorsey and his Orchestra took over comedian Jack Pearl's radio show in 1937
By 1939, Dorsey was aware of criticism that his band lacked a jazz feeling. He hired arranger Sy Oliver away from the Jimmie Luncefordband. Sy Oliver's arrangements include "On The Sunny Side of the Street" and "T.D.'s Boogie Woogie"; Oliver also composed two of the new band's signature instrumentals, "Well, Git It" and "Opus One". In 1940, Dorsey hired singer Frank Sinatra from bandleaderHarry James. Frank Sinatra made eighty recordings from 1940 to 1942 with the Dorsey band. Two of those eighty songs are "In The Blue of Evening" and "This Love of Mine". Frank Sinatra achieved his first great success as a vocalist in the Dorsey band and claimed he learned breath control from watching Dorsey play trombone. In turn, Dorsey said his trombone style was heavily influenced by that of Jack Teagarden. Among Dorsey's staff of arrangers was Axel Stordahl who arranged for Frank Sinatra in his Columbia andCapitol records years. Another member of the Dorsey band was trombonist Nelson Riddle, who later had a partnership as one of Sinatra's arrangers and conductors in the 1950s and afterwards. Another noted Dorsey arranger, who in the 1950s, married and was professionally associated with Dorsey veteran Jo Stafford, was Paul Weston. Bill Finegan, an arranger who left Glenn Miller's civilian band, arranged for the Tommy Dorsey band from 1942 to 1950