Historical clue formulations

• Jack who hosted "The Morning Show" and "The Tonight Show" — 2024-12-04
• Jack of old TV — 2022-09-11
• Jack of 1950s TV — 2022-06-08
• Talk show host Jack — 2021-12-21
• Jack who pioneered late-night talk — 2021-04-20
• Jack who once hosted "The Tonight Show" — 2020-12-28
• Early talk show host Jack — 2019-05-13
• 1950s-'60s TV emcee Jack — 2019-03-06
• Carson's predecessor on "The Tonight Show" — 2018-10-16
• Allen's replacement on "The Tonight Show" — 2017-10-18
• Jack of the old "Tonight Show" — 2017-08-08
• Late-night host before Carson — 2016-01-20
• Jack in the box, once? — 2015-11-22
• Allen's successor on late-night TV — 2015-01-11
• Onetime host of CBS's "The Morning Show" — 2014-11-29
• Host of 1950s TV's "Bank on the Stars" — 2014-08-29
• "Up to ___" (1952 game show) — 2013-11-30
• Onetime host of "The Tonight Show" — 2011-10-07
• "Up to ___," 1952 game show — 2011-04-03
• Carson predecessor — 2010-01-12
• Subject of the documentary "Smart Television" — 2009-12-16
• 1950s-'60s NBC host — 2009-11-27
• Jack who once hosted "The Tonight Show" — 2009-06-29
• Carson's predecessor — 2009-06-21
• See 6-Across — 2009-06-01
• Host who said "I kid you not" — 2009-01-07
• 1950s-'70s TV host — 2008-09-21
• Jack who quipped "A funny thing happened to my mother one day: Me" — 2008-06-24
• Jack who pioneered late-night talk — 2008-06-23
• Jack of early late-night TV — 2007-10-22
• Carson's predecessor — 2007-04-10
• Carson predecessor — 2007-01-09
• Onetime host of "The Morning Show" and "The Tonight Show" — 2006-11-12
• Early late-night name — 2006-09-20
• Punnily titled 1952 quiz show "Up to ___" — 2005-05-14
• Hugh Downs was his announcer — 2005-03-18
• Old late-night host — 2004-12-01
• Carson's predecessor on "The Tonight Show" — 2004-08-23
• Subject of the documentary "As I Was Saying" — 2004-08-01
• "I kid you not" speaker — 2003-11-05
• Jack of old TV — 2003-07-11
• Carson predecessor — 2003-05-13
• Early late-night name — 2003-05-07
• TV host with the instrumental theme "I-M-4-U" — 2003-04-27
• Carson's predecessor — 2003-04-23
• Host before Carson — 2002-07-23
• 1952 quiz show "Up to ___" — 2002-07-05
• TV's Jack — 2001-11-11
• Carson's predecessor — 2001-05-16
• Early late-night host — 2000-11-28