Organized by a small, enthusiastic group of former corps members, the Alumni Corps quickly grew and continues strong, currently numbering more than one hundred members. Originally open only to former Caballeros members, the Caballeros Alumni Corps now welcomes all qualified applicants. Currently the corps' membership is made up of players from several states, and spans all five decades of the Caballeros' history.

In addition to assisting the competition corps wherever and whenever possible, one of the purposes for launching the Alumni Corps was to return to some of the great music from the fifties, sixties, and seventies, bringing back memories for older players and fans, and exposing younger fans to the music that made the Caballeros famous in earlier years. As one of the few alumni corps with a full field show, however, the Caballeros Alumni Corps remains popular.

The corps has been in great demand from the start, but unlike the competition corps, the Alumni Corps maintains a somewhat less rigorous schedule, and is strictly an exhibition and parade corps.

Peter Bishop is the corps director and business manager, and on the field, the corps is in the capable hands of Chuck Bishop, who holds the distinction of having been a drum major with all three Hawthorne corps: the Muchachos, the Caballeros, and now, the Caballeros Alumni Corps. Chris Sortino is the current alumni president.

The alumni corps is associated with Hawthorne American Legion Post 199.