[12] The school was ranked 83rd in the nation and fourth in New Jersey on the list of "America's Best High Schools 2012" prepared by The Daily Beast / Newsweek, with rankings based 25% each on graduation rate, matriculation rate for college and number of Advanced Placement / International Baccalaureate courses taken per student, with 10% based on average scores on the SAT / ACT, 10% on AP/IB scores and an additional 5% based on the number of AP/IB courses available to students; It was the highest-ranked open enrollment (non-selective / non-magnet) school in the state.

[27] The Millburn High School Millers[2] compete in the Super Essex Conference, which is comprised of public and private high schools in Essex County and was established following a reorganization of sports leagues in Northern New Jersey by the New Jersey State Interscholastic Athletic Association (NJSIAA).

[30] The football team competes in the Freedom White division of the North Jersey Super Football Conference, which includes 112 schools competing in 20 divisions, making it the nation's biggest football-only high school sports league.

[34] The Millburn baseball program set a school record in 2008 with 27 wins, finishing 27–5 with conference and winning a North II, Group III state sectional title with a 9–8 win over John F. Kennedy Memorial High School of Iselin after trailing by 8–0 in the game's fourth inning before losing 17–8 to Northern Valley Regional High School at Old Tappan in the Group III semifinal.

[35][36][37] In 2015, the Millers won both the Group IV state championship and the New Jersey state title with an 11–3 win against Williamstown High School, the team's first, under coach Brian Chapman, who was later named one of the ABCA / Diamond Club National Coaches of the Year.

[38] in 2017, the program won its second Group IV title with a 10–5 win against Hunterdon Central Regional High School in the playoff finals.

In the North II, Group III state sectional championship, the team came in as the 8th seed, falling to top-ranked Irvington High School 47–14 in the first round of the tournament.

[43] The field hockey team won the North II, Group III state sectional title in 1979 and 1982.

For the first time in 36 years, the 2018 Millburn varsity field hockey team won the North II, Group III state section title, before losing in the first round of the Group III Tournament in double overtime against Warren Hills Regional High School.

[47] The 1967 team won the Group III title, defeating semifinals opponent Northern Valley Regional High School at Demarest 2½-½ and beat Summit 3–0 in the finals.

[49] The 2007 team won the North II, Group III state sectional title with a 4–1 win vs. Ridge High School.

Udland became the school's fourth individual Meet of Champions winner, joining All-Americans Tom Lester (1966 in the discus), Steve O'Connell (1975 and 1976; Mile) and Will Nesbitt (1980; pole vault)[51][52] as well as Marty O'Hare (1973, long jump).

[53] In 2006, team won the Group III title at Mercer County Park after defeating Seneca High School 5–0 in the semifinals and Moorestown 3–2 in the finals.

[54] The 2007 girls' tennis team won the North II, Group III state sectional championship with a 5–0 win over Holmdel in the tournament final[55] and moved on to take the Group III state championship with a 3½-1½ win over Wall Township in the semifinals and Moorestown in the finals by a 5–0 score.

[63] The 1986 team finished the season with a record of 24-1-1 after being declared as co-champion with Delran following a 1–1 tie in the tournament final played at Trenton State College.

[64] The 2008 boys' varsity soccer team won the Group III state sectional championship with a 3–0 win over Moorestown High School.

The team also captured the Essex County and Northern Hills Conference championships, finishing with a record of 23-2 and ranked 3rd in the state of New Jersey and 32nd in the nation.

[67] The girls' soccer team won the Group III state title in 2010 after defeating Hopewell Valley Central High School in the tournament final.

An item included in Word was winner of a 2009 Gold Medal from the Columbia Scholastic Press Association.

Recent productions have included The Drowsy Chaperone, Young Frankenstein,[76] Pal Joey, Into the Woods, Cheaper by the Dozen, Dirty Rotten Scoundrels, How to Succeed in Business Without Really Trying, Metamorphoses, Thoroughly Modern Millie and Woody Allen's Don't Drink the Water.

Between 80 and 100 students each year are involved with the musical and dramatic productions, whether as onstage performers, backstage and technical crew, set builders or members of the pit orchestra.

They went on to win the grand finals, making them the 2018-19 Vex World Champions out of approximately 11,400 teams worldwide.

[84] Miron graduated in 1974 from Millburn High School, where he was a member of the wrestling team, and placed number one in the state in 1973 in the 157 lb.

The father and son were accused of beating the other student with a baseball bat and were charged with aggravated assault and weapons possession.