Lower Merion A Cappella was founded in the 2003-2004 school year with the creation of Ace Harmony. The following year Ace’s Angels was introduced and the two groups dominated LMAC for the next ten years.

After the 2013-2014 school year the decision was made to bring other stylistic options to LM A Cappella, broadening its reach and bringing new experience to its singers. Ars cantiqua was the first of these groups to be added, beginning in the 2014-2015 school year. The following year another new group, Standard Voices, brought yet another genre of music into the LM A Cappella family.

The 2016-2017 school year will see the return of Ace’s Angels, but will also see the launching of yet another new group: Flying Aces.

Throughout its existence LM A Cappella has felt strongly connected to its alumni; students who devoted large amounts of time, energy, and emotion to help make LMAC groups succeed every year. Members of Ace Harmony, Ace’s Angels, and Flying Aces are all assigned a unique number indicating their place in the history of their respective group(s). Other LMAC groups do not follow this numbering convention.