The club hosts high goal polo matches throughout the summer, tournaments typically beginning in June and concluding in September.

Players past and present have included: 2019 East Coast Open Teams: Audi White Birch Polo Team (Chris Brant, Joaquin Panelo, Matias Magrini and Toro Ruiz) Monterosso (Alessandro Bazzoni,[7] Ignacio Toccalino, Naco Taverna, Santino Magrini) Postage Stamp Farm (Annabelle Gundlach, Brandon Phillips, Lerin Zubiaurre, Tomas Garcia Del Rio) Los Violines (Christophe Landon, Michel Dorignac, Tommy Biddle, Pedrinho Zacharias) Monterosso Vikings (Siri Bazzoni, Peke Gonzalez, Barto Castongola, Ignacio du Plessis) It was established in 1981 by Peter M. Brant, who started the White Birch Polo Team.

In 1981 Greenwich Polo Club was officially established by Brant with eight founding members including Peter Busch Orthwein, Mickey Tarnapol, Adam Linderman, Marty Gross, Charles Johnson, Henryk de Kwiatkoski, Geofrey Kent and Michael Shore.

The trophy was a George III silver cup made by silversmiths John Wakelin and William Taylor in London in 1784.

In 1922, two years after his passing, his friends and teammates played for the first Monty Waterbury Cup, at the Meadow Brook Club, in Westbury, Long Island, were it became a perpetual challenge trophy for an impressive 28-year stretch.

In 1954, however, the U.S. Open changed venues to Illinois, and the tournament was integrated into the Northeastern Circuit schedule, where it slowly receded into the background until its resurgence in 1975.

According to Horace Laffaye in his book “Polo in the United States,” the 1975 revival was spearheaded by Circuit Governor George Haas, Jr., whose Fairfield County Hunt Club won the tournament that year.

While polo is recently associated with Argentinean culture, the American Cup celebrates the monumental contributions and advancements of the sport made by those in the United States.

The Northeast of the United The first-ever American Cup at Greenwich Polo Club in 2019 had players and spectators holding their breath until the final whistle.

After cruising through a four-team penalty shoot-out, Postage Stamp Farm and Reelay punched their tickets to the final match.

Reelay came out of the gates strong with an early 4–0 lead, thanks to first-chukker goals by Will Tomita and Mariano Gonzalez, but nothing was going to break Postage Stamp Farm's determination.

Audi Polo’s Marc Ganzi, Miguel Novillo Astrada, Nic Roldan and Juancito Bollini, defeated White Birch, consisting of Santino Magrini, Hilario Ulloa, Mariano Aguerre and Peter Brant by 14–13 in overtime to win the USPA East Coast Open championship.

[21] September 8, 2019: The 2019 season at Greenwich Polo Club capped off with a thrilling East Coast Open victory by Postage Stamp Farm (Annabelle Gundlach, Brandon Phillips, Lerin Zubiaurre and Tomas Garcia del Rio), adding their name for the first time to the historical Perry Trophy, amongst many of the game's greatest.

In the final, Postage Stamp Farm defeated Monterosso by a score of 12–10 in front of a record Sunday crowd, with perfect weather and completely packed East and West lawns.