He played college basketball for one season with the UCLA Bruins before being selected by the Philadelphia 76ers in the first round of the 2009 NBA draft with the 17th overall pick.

[7] Holiday attended Campbell Hall School in the Los Angeles district of Studio City, California.

[9][10] In 2008–09, Holiday played alongside fellow future NBA player Darren Collison in the backcourt at UCLA.

[23] Holiday returned to action much later than originally expected, coming off the bench against the Phoenix Suns on April 10 after missing 41 games.

[26] On November 18, 2016, Holiday made his season debut after missing the Pelicans' first 12 games while on a leave of absence to care for his wife.

[31] Six days later, he made five three-pointers in the fourth quarter, when he scored 19 of his 34 points, helping the Pelicans defeat the Philadelphia 76ers 131–124.

[49] On March 4, 2021, Holiday scored 15 points in 23 minutes, and hit a game-winning 11-foot jump shot in a game against the Memphis Grizzlies.

On his way to an NBA First Team All Defense selection, Holiday averaged a team-high 1.63 steals per game for the Bucks, which was fifth best in the league.

[51] On May 24, 2021, Holiday recorded a postseason career-high 15 assists, alongside 11 points and seven rebounds, in a 132–98 Game 2 victory over the Miami Heat in their first-round playoff series.

[53] In Game 5 of the NBA Finals against the Phoenix Suns, Holiday put up 27 points, four rebounds, 13 assists, and recorded a critical steal from Devin Booker, which led to an alley oop to Giannis Antetokounmpo with less than 20 seconds left in the fourth quarter to help the Bucks win 123–119.

[56][57] On December 15, 2021, Holiday recorded 26 points and 14 assists in a 114–99 victory over the Indiana Pacers in which Milwaukee was missing its other two "big three" members Giannis Antetokounmpo and Khris Middleton.

[58] On December 17, Holiday scored a career-high 40 points, grabbed five rebounds and delivered five assists, along with two steals in a 116–112 overtime loss against his former team, the New Orleans Pelicans.

[59] On March 2, 2022, Holiday banked in a driving layup with 1.9 seconds left as the Bucks rallied from a 14-point deficit in the final six minutes to narrowly beat the Miami Heat 120–119.

[60] The following game, Holiday scored 16 of his 26 points in the fourth quarter (10 in the final 5 minutes) along with eight rebounds and five assists in a 118–112 victory over the Chicago Bulls.

[63] On May 7, in Game 3 of the Eastern Conference Semifinals, he scored 25 points including the game-winner in a narrow 103–101 victory over the Boston Celtics.

[64] Four days later in Game 5, Holiday stopped Marcus Smart on the Celtics' last two plays, recording a block and a steal to preserve the Bucks' lead in their 110–107 comeback victory as they overcame a 14-point fourth-quarter deficit.

[67] On October 31, 2022, Holiday recorded 25 points (including a game-securing step-back three-pointer with 45 seconds left), 10 assists and seven rebounds while leading the Bucks to a narrow 110–108 victory over the Detroit Pistons.

[68] On January 16, 2023, he scored a then season-high 35 points and delivered 11 assists on 13-of-19 shooting, 5-of-8 from three and 4-of-4 from the free throw line in a 132–119 victory over the Indiana Pacers.

[69] In the next game, Holiday upped his season high to 37 points, along with six rebounds, seven assists and two steals in a 130–122 victory over the Toronto Raptors.

Holiday led the Bucks to a 2–1 week with averages of 33.3 points, 9.3 assists, 4.7 rebounds and 1.7 steals per game while shooting 56.9% from the field and 47.8% from three.

[74] On March 29, he scored a career-high 51 points, along with eight rebounds and eight assists on 67% field goal percentage in 32 minutes, leading the Bucks to a 149–136 victory over the Indiana Pacers.

[75] On April 5, Holiday recorded 20 points, eight rebounds and a season-high 15 assists in a 105–92 victory over the Chicago Bulls, wrapping up the top seed in the NBA playoffs for the Bucks.

[79] On September 27, 2023, Holiday, alongside Deandre Ayton, Toumani Camara and a 2029 first-round draft pick was traded to the Portland Trail Blazers as part of a three-team deal that sent Damian Lillard to the Milwaukee Bucks and Grayson Allen, Jusuf Nurkić, Nassir Little and Keon Johnson to the Phoenix Suns.

[80] Four days later, Holiday was traded to the Boston Celtics in exchange for Robert Williams III, Malcolm Brogdon and two future first-round draft picks.

[82] In Game 1 of the Eastern Conference Finals against the Indiana Pacers on May 21, Holiday recorded a season-high 28 points, seven rebounds, eight assists and three steals in a 133–128 overtime victory.

[84] He also became the first player in NBA history to average at least 18 points, seven rebounds and five assists with 50-40-100 shooting splits in a conference finals series.