Question: Who was best known for leading the NBC Orchestra on "The Tonight Show Starring Johnny Carson" that recorded and played with Harry Sheppard?

Context paragraphs:
The Tonight Show Band: "The Tonight Show" Band is the house band which plays on the American television variety show "The Tonight Show".  From 1962 to the 1990s, during the years the show was known as "The Tonight Show Starring Johnny Carson", the band was a 17-piece big band, and was an important outlet for jazz on American television.  During the Carson era, the band was always billed as "The NBC Orchestra" (not to be confused with the NBC Symphony Orchestra) and sometimes "Doc Severinsen and the NBC Orchestra".  The current Tonight Show Band is Philadelphia-native hip hop band The Roots under the tenancy of Jimmy Fallon.

Johnny's Theme: "Johnny's Theme" is an instrumental jazz song played as the opening theme of "The Tonight Show Starring Johnny Carson" from the show's inception in 1962 through its finale in 1992.  The piece was composed by Paul Anka and Johnny Carson, based on a previous composition by Anka.  It was performed by The Tonight Show Band, which released an arrangement by Tommy Newsom in 1986 as part of its Grammy Award-winning eponymous debut album.  The single release also garnered a Grammy nomination.

Daniel Rosen: Daniel Rosen is an American comedian, juggler and game show announcer.  He began his career with unicycle, juggling and magic acts in high school.  Johnny Carson discovered Rosen when he was a teen and made him a regular guest on The Tonight Show Starring Johnny Carson.  The Tonight Show exposure and Carson's endorsement led him be the announcer and writer on "The Late Show", a talk show that was on Fox.

Tommy Newsom: Thomas Penn "Tommy" Newsom (February 25, 1929 – April 28, 2007) was a saxophone player in the NBC Orchestra on "The Tonight Show Starring Johnny Carson", for which he later became assistant director.  Newsom was frequently the band's substitute director, whenever Doc Severinsen was away from the show or filling in for announcer Ed McMahon.  Nicknamed "Mr. Excitement" as an ironic take on his low-keyed, often dour persona, he was often a foil for Johnny Carson's humor.  His brown or blue suits were a marked contrast to Severinsen's flashy stage clothing.

Harry Sheppard (musician): Harry Sheppard is a jazz vibraphone player who has recorded and played with Roy Eldridge, Charlie Shavers, Ben Webster, Red Allen, Cozy Cole, Sol Yaged, Georgie Auld, Clark Terry, Al Cohn, Zoot Sims, Lana Cantrell, Billie Holiday, Benny Goodman, Duke Ellington, Ben Webster, Barbra Streisand, Doc Severinsen, and Coleman Hawkins.  Sheppard grew up in Worcester, Massachusetts, moved to New York City then to Houston in 1985 to care for his daughter, who died of cancer about a year later.

Doc Severinsen: Carl Hilding "Doc" Severinsen (born July 7, 1927) is an American pop and jazz trumpeter.  He is best known for leading the NBC Orchestra on "The Tonight Show Starring Johnny Carson".

The Tonight Show Starring Jimmy Fallon: The Tonight Show Starring Jimmy Fallon is an American late-night talk show hosted by Jimmy Fallon, on NBC.  The show premiered on February 17, 2014, and is produced by Broadway Video and Universal Television.  It is the seventh incarnation of NBC's long-running "Tonight Show" franchise, with Fallon serving as the sixth host.  The show also stars sidekick and announcer Steve Higgins and house band The Roots.  "The Tonight Show" is produced by Katie Hockmeyer and executive-produced by Lorne Michaels.  The show records from Studio 6B in Rockefeller Center, New York City.  This was the first version of "The Tonight Show" filmed in New York City since "The Tonight Show Starring Johnny Carson" in 1972.

Donald Ashworth: Donald William Ashworth (born March 16, 1931) is a musician who was a member of "The Tonight Show Band" for thirty years before retiring in 1995.  Ashworth played woodwind instruments with the group starting from Johnny Carson's first week as host of "The Tonight Show" in October 1962 (when the band was referred to generically as "The NBC Orchestra") until his final show on May 22, 1992.  For its first 10 years, Carson's "Tonight Show" was based in New York City with occasional trips to Burbank, California; in May 1972, Ashworth moved from New York City to Southern California when the show moved permanently to Burbank.  He was often seen on the show when Carson played "Stump the Band", where studio audience members asked the band to try to play obscure songs given only the title.

John Twomey (musician): John Twomey is a manualist who appeared on NBC's The Tonight Show Starring Johnny Carson in 1972 and 1974.  He is credited with bringing manualism to the public stage, as his performance of "Stars and Stripes Forever" was seen by millions of people and was included in the "Best of Johnny Carson" collection.  Twomey also coined the term "manualism," as he introduced himself as a "manualist" in the show.  Twomey was a regular guest of Johnny's after that first appearance all the way until Johnny retired from "The Tonight Show".

Conte Candoli: Secondo "Conte" Candoli (July 12, 1927 – December 14, 2001) was an American jazz trumpeter based on the West Coast.  He played in the big bands of Woody Herman, Stan Kenton, Benny Goodman, and Dizzy Gillespie, and in Doc Severinsen's NBC Orchestra on "The Tonight Show Starring Johnny Carson".  He played with Gerry Mulligan, and on Frank Sinatra's TV specials.  He also recorded with Supersax, a Charlie Parker tribute band that consisted of a saxophone quintet, the rhythm section, and either a trumpet or trombone.

Supporting paragraphs: Harry Sheppard (musician) Doc Severinsen
Answer: Doc Severinsen