The personal tension traces to two strands that predate their frequent Kentucky–Louisville matchups. First, Pitino claimed he helped Calipari land the UMass job in 1988 and later said he "wrote a $5,000 check," an account that Calipari and others disputed when it resurfaced in 2011 — creating an early, recurrent personal wrinkle between the men [13]. Second, Pitino's March 2001 hire at Louisville — after his earlier tenure at Kentucky — placed him directly across from Calipari on the state stage and intensified coach-level attention around each meeting [1][2]. Those elements combined with on-camera, pregame rhetoric (including Pitino's televised lines before the 2012 Final Four) to make their interactions about personalities as much as programs [14][16][4].
The relationship is best described as complicated: public barbs persisted through the 2012 Final Four era, but the two have since engaged in more direct conversation, including Pitino's appearance on Calipari's "Cal Cast" in January 2017 where Pitino called the relationship "cordial" and "professional" [17]. Pitino's 2017 firing amid the FBI/Adidas probe and Louisville's institutional issues changed the rivalry's context but did not erase the coaches' prior public exchanges [6].
No single-source evidence shows ongoing personal hatred; their relationship combined public barbs (notably around the 2012 Final Four) and contested origin stories with later, recorded cordial moments such as Pitino's January 2017 appearance on Calipari's 'Cal Cast' where Pitino described the relationship as 'cordial' and 'professional' [14][4][17].
Two main factors: Pitino's public claim that he helped Calipari land the UMass job (including a '$5,000' anecdote reiterated in 2011 and disputed by others) and Pitino's 2001 hiring at Louisville, which put him directly opposite Calipari on the Kentucky stage; those strands informed later televised exchanges, including pregame media around the 2012 Final Four [13][1][16][4].
They are not close personal friends; on record they describe a professional, cordial relationship — Pitino said in 2017 on Calipari's podcast that they'd never had a bad relationship and called it 'cordial' [17]. Institutional events after 2017 shifted focus away from coach-to-coach publicity, but the recorded podcast remains the clearest example of reduced public antagonism [6][17].