In 1909, at the Amateur Athletic Union (AAU) metropolitan senior championships, held at Travers Island, New York, Rosenberger takes first place in the 100- and 220-yard dash. The following week, he is part of the Irish American Athletic Club’s four-man relay team that breaks the world record for the one-mile relay with a time of 3 minutes, 20 2/5 seconds. The other three men on the record-breaking team are C. S. Cassara, Melvin Sheppard, and William Robbins.
On April 9, 1911, Rosenberger anchors the Irish American Athletic Club 4×440-yard relay team that breaks the world record at Celtic Park, Queens, New York City and sets the first International Amateur Athletic Federation– recognized world record for 4×440-yard or 4×400-meter relay race, in time of 3 minutes and 18.2 seconds. The other members of the world record-setting team are Harry Gissing, Melvin Sheppard and Harry Schaaf.
Rosenberger participates in the 1912 Summer Olympics in Stockholm but is eliminated in a 400 metres semifinal. The following year he competes in Australia with the AAU team, and in 1915, he becomes the coach for the Long Island Athletic Club.
Following his retirement from track and field, Rosenberger later works as an auditor and is a track coach at St. John’s University.
The Irish American Athletic Club, an amateur athletic organization based in Queens, New York, is established on January 30, 1898, originally as the Greater New York Irish Athletic Association. They shorten the name to the Irish American Athletic Club a few years later. They purchase a plot of land in what is then called Laurel Hill, Long Island, near Calvary Cemetery, Queens, and build a state-of-the-art athletic facility on what is farmland. The stadium, called Celtic Park, formally reopens after renovations on May 9, 1901, and until the facility is sold for housing in 1930, some of the greatest American athletes train or compete on Celtic Park’s track and field. The Irish American Athletic Club adopts a winged fist adorned with American flags and shamrocks as their emblem, with the Irish Gaelic motto “Láim Láidir Abú” or “A strong hand will be victorious,” and are often referred to as the “Winged Fists.” At one time they have clubs in Boston, Chicago, San Francisco and Yonkers, New York.
The Irish American Athletic Club is predominantly composed of Irish-born and first generation Irish American athletes, but many of the athletes who compete for the Winged Fist organization are neither.
The Irish American Athletic Club wins the Amateur Athletic Union national outdoor track and field team championship titles in 1904, 1906, 1907, 1908, 1910, 1911, 1912, 1913, 1914 and 1916. They also win the national indoor track and field team championship titles in 1906, 1908, 1909, 1911, 1913, 1914 and 1915. Individual athletes of the IAAC win 81 national outdoor championships titles and 36 individual national indoor championship titles.
In 1912–13, 1913–14, 1914–15 and 1916–17 the Irish American Athletic Club has a team, the New York Irish-Americans, represented in the American Amateur Hockey League. The team is coached by James C. “Jimmy” O’Brien and has on its roster for various seasons future NHL players Tom McCarthy and Moylan McDonnell. John McGrath and Patsy Séguin also play for the club.
Before the largest crowd that has ever assembled to see a track meet in the United States, on September 9, 1916, the Irish American Athletic Club defeats the New York Athletic Club at the Amateur Athletic Union’s National Championships, by a score of 38 to 27. Before a crowd of 30,000 spectators at Newark, New Jersey‘s Weequahic Park, the Irish American Athletic Club wins what is to be their last national championship title. The club disbands a year later when the United States becomes a combatant in World War I.