[12] In the early 2000s, the AFUHSD began to rely heavily on bonds to fund Millennium High School, facing a growing population of residents in the West Valley region.

To alleviate these issues, the AFUHSD implemented multiple funding phases: the first, approved in 1998 for $11 million, added 27 classrooms to Millennium.

In 2014, Millennium partnered with a Dutch Bros. Coffee store in Goodyear; for a single day, proceeds from large drinks sold at the store would be donated to Millennium, and offered customers an incentive for purchasing a large drink.

[16] In June 2022, Millennium began construction on a $16.25 million gymnasium, dubbed the "Rise and Roar Center", with the efforts of McCarthy Building Companies and BWS Architects.

[17] As of the 2021–2022 school year, Millennium had an enrollment of 1,965 students and 92.30 teachers (on FTE basis), for a student–teacher ratio of 21.29.

[4] The same year, the Arizona Department of Education awarded Millennium High School an "A" rating.

[24] Students at Millennium can take Advanced Placement (AP) classes, focusing on English, mathematics, science, history, art, and foreign languages.

[25] As part of the AFUHSD, sophomores, juniors, and seniors at Millennium can attend online classes through the school.

[26] A ProPublica report in 2016 found that around a fifth of students take the SAT or ACT, and 5% are in a gifted and talented program.

[25] The Arizona Board of Regents found that, for the 2015–2016 school year, 58.2% of students attended some form of post-secondary education.

[32] In 2020, the Tiger girls golf team placed eighth at the AIA Division II state tournament.