The partnership was a reaction to perceived inflexibility of the American Legion and VFW, who were the primary sponsors of competing drum corps and the hosts of the only high-prestige national championships.

[3]: 47  Another source of contention was low-to-nonexistent appearance fees paid to independent corps who were neither sponsored nor affiliated with any veterans post.

[a] Its members were: 27th Lancers, Garfield Cadets, Boston Crusaders, Blessed Sacrament Golden Knights, and Blue Rock.

[2] Despite objections from veterans associations, and boycotts by adjudicators, both the Combine and the Alliance remained intact for the 1971 competitive season.

[3]: 321  Also invited to the meeting were the Anaheim Kingsmen, Argonne Rebels, and De La Salle Oaklands.

Members also agreed to remain united if boycotting a particular event, show sponsor, or business, such as the boycott against Fleetwood Records over rights issues, if such an action proved necessary.

The Anaheim Kingsmen Drum and Bugle Corps was named the inaugural DCI World Champion.

American Legion and VFW posts in the Midwest or New England host drum corps competitions as fundraising events, some of which are sanctioned by DCI.

On March 25, 2020, in response to the coronavirus pandemic, member corps voted unanimously to cancel the 2020 competitive season.

[17] As the self-styled "Marching Music's Major League", DCI's mission is to create an environment for participating corps "to engage in education, competition, entertainment, and the promotion of individual growth."

The evaluation requires corps to submit data on their financial health, fundraising capacity and income, participants, staffing, and explanations of their administrative structure.

The corps must then be approved by a majority of other members at a meeting following World Championships, usually the annual rules congress later in the year.

Corps from those associations are allowed to compete at sanctioned competitions, and at World Championships in International Class.

[21] Individual drum corps derive a large part of their revenues from marketing their product, specifically memorabilia and souvenir sales.

DCI derives income from ticket sales, and is the sole distributor of official media, such as championship DVDs and audio CDs.

[25] Frequent hosts of the broadcasts and streaming events include former WWAY news anchor Steve Rondinaro, and percussionist Dennis DeLucia.

[26] In 2013, DCI launched two new competitive musical activities for small groups: SoundSport and DrumLine Battle.

The stated goal of SoundSport is to provide a competitive performance experience in a low-cost, local setting.

[28] Southwind, inactive from 2007 to 2013, competed as a SoundSport team in 2014, and returned to competition as an Open Class member in 2015.

Competing drumlines are staged in two competitive zones opposite each other, with each demonstrating their skills as an ensemble in alternating rounds of two minutes each.

[30] In 2014, E-Sarn from Thailand, competed in the DrumLine Battle held during World Championship week, defeating fifteen other competitors.

[34][32] The activities are held in conjunction with a local DCI competition, and World Class corps partner.

However, the second week of August has been the preferred date due to trends in scholastic and collegiate schedules which pushed the start of the school year from early-September to late-August.

DCI utilizes a single adjudication handbook with corps subdivided by size, and not skill level.

Currently, DCI groups corps from the United States and Canada into three classes based on competitive level.

Corps in this class are allowed to follow the guidelines of their national governing body, such as: no age restrictions, smaller membership requirements, or the use of woodwind instruments.