As of the fall of 2007, Centennial had teamed up with Score Atlanta and Turner Broadcasting to begin showing live broadcasts of the school's home sports games. This was the first program ever to do this with high school students.
Model United Nations Centennial's 2008 Model United Nations delegations of Albania and Venezuela placed first and third out of over 200 delegations in the National High School Model United Nations competition, with Albania coming in first, and Venezuela third respectively. In March 2009, Centennial competed again in the national competition, representing France, and repeated in first place out of over 250 schools. In 2011, Centennial returned to the top ten, placing eighth in the nation. According to Best Delegate, "Centennial placed a distant third behind Port Charlotte High School and Gulf Coast High School at their hometown Georgia Tech GTMUN conference to begin the Fall, but the team roared back at Nationals NHSMUN to win Outstanding Large Delegation. We valued this win at one of the most competitive conferences in the nation much more than their early-season head-to-head placing at the smaller, regional GTMUN in determining where they would place in the standings — at the end of the season, Centennial won one of the top team awards in the circuit. On a side note, GTMUN Secretary-General Kelsie Riemenschneider is among its alumni in the college ranks." Also in 2011, Centennial's Model UN team hosted its first Model UN Conference, called MiniMUN, for area middle school students. MiniMUN continues to expand and bring in middle school students from all over Georgia. The conference is entirely student-run. In 2012, Centennial ranked ninth in the nation, according to Best Delegate: "Centennial continues to be one of the strongest teams from the Southeast. The team won Best Delegation at the Southern United States SUSMUN conference and placed third at an increasingly competitive Georgia Tech GTMUN. The team primarily participates at in-state conferences but teams around the country will recognize them when they travel to participate at Nationals NHSMUN (Centennial won a delegation award there last year)." As of May 29, 2013, Best Delegate ranked Centennial's Model UN team number six in the nation. During the 2012–2013 school year, Centennial won the Award of Distinction at the National Model United Nations, the Best Small Delegation Award at the HMUN, the Award of Distinction at Southern States Model United Nations, and won more delegation awards at UGAMUN and Georgia Tech GTMUN. In 2014 Centennial received both the Award of Excellence and the Research and Preparation Award of Excellence at NHSMUN. This was followed in 2015 and 2016 with the Award of Merit at the same conference. In 2016–2017, the team competed at GTMUN, Vanderbilt's Model United Nations Conference XIII, Model Arab League, and UGAMUNC receiving several awards, including Best Position Paper, Honorable Mention and Outstanding Delegation awards for individual and overall delegations. In the 2015–2016 school year, Centennial added a class in International Affairs designed to cultivate young delegates through mentorship and instruction by senior members of the team. According Best Delegate's 2015–2016 high school rankings, Centennial MUN team ranks top 150 teams in the nation. Centennial is advised by the Social Studies Department Chair Mack Hennessey.
Athletics The 2002 Knights football team went 10–0, marking the only undefeated regular season in Centennial's history.This was partly due to the elite coaching of Harris Seidband, who was recently hired by the Alabama Crimson Tide to join the team as an offensive lineman coach. The region 6-AAAAA champion The Knights lost in the second round of the state playoffs to eventual state champion
Parkview High School. Centennial's first team state championship was won by the 2006 girls' varsity swim team. Centennials boys swim team holds the GHSA state record for the 200 medley of 1:31.71, swam by Aidan Saunders, Justin Bender, Sebastien Sergile and Caleb Paek in 2022 Both Centennial's boys' and girls' varsity cross country teams qualified for the state meet eight years in a row, from 2007 to 2013. In 2010, the boys' and girls' varsity teams both finished first at the regional meet. Senior Brooke Koblitz led the girls' race and broke the school record for 3.1 miles, finishing at 18:40. Junior Kane Davis finished first in the boys' race. The team also sponsors the annual Firstgiving Sam Robb Memorial 5k and Fun Run which raises money for the Cure Childhood Cancer fund and honors former Centennial student Sam Robb.
Marching Band Under the direction of band director Matthew Everhart and assistant band director Michelle Jiang as well as their Choreography Instructor and Drumline teacher, Robert Dickens Jr., the Centennial Marching Band has performed for several years. Their 2025 performance, Stargazer, conducted by drum majors Abriella Swann and Gray Reza, placed third in their first competition and got first in class AA overall band at the White Columns Invitational. The marching band is part of the 2A division. ==Notable alumni==