Countess and Count László Széchenyi, circa 1908.
|Born||Count László Széchenyi de Sárvár-felsővidék
February 18, 1879
|Died||July 5, 1938
|Occupation||Austro Hungarian military officer, Imperial Chamberlain, diplomat, venture capitalist|
|Known for||Husband of Gladys Vanderbilt|
|Notable work||Hungary’s first Minister to the United States
Hungary’s first Minister to the Court of Saint James in the United Kingdom
|Spouse(s)||Gladys Vanderbilt (m. 1908–1938; his death)|
Count László Széchenyi de Sárvár-felsővidék (born Széchenyi László Jenő Mária Henrik Simon in Horpács, 18 February 1879–Budapest, 5 July 1938) was an Austro Hungarian military officer, Imperial Chamberlain, diplomat and venture capitalist. His great-uncle was István Széchenyi. László Széchenyi married Gladys Vanderbilt, the youngest daughter of Alice Claypoole Gwynne and Cornelius Vanderbilt II.
All of the brothers were Reserve Lieutenants in the Imperial Hussars as well as Chamberlains at the Court.
Count László Széchenyi was the inventor of the submarine wireless telegraphy, for sending and receiving sound-wave vibrations underwater, and started the Submarine Wireless Company to produce it.
By 1908, Count László Széchenyi de Sárvár-felsővidék was the most prominent member of his family, which was quite numerous. He possessed two great estates in Hungary, Oermezo Castle, which is about three hundred years old and 4,000 acres, in the County of Templen, and Lagoshara Pusbla, a Summer place of about 4,300 acres, in the County of Somogy. The Count also owned a one-story, ten room house at 14 Eotvoss-street in Budapest. 
Shortly before the War, Count László Széchenyi de Sárvár-felsővidék tried to become a financial Napoléon in Hungary and met his Waterloo very quickly. He is said to have lost $4,000,000 which is supposed to have come largely from his wife. He was a member of the ‘Magnates Group’ which speculated in mines, railroads and other enterprises. They failed to calculate the impact of the World War, and suffered a complete smash as a result of the fall in value of their shares.
Count László Széchenyi presented his credentials as Hungary’s first Minister to the United States on January 11, 1922. He served until March 31, 1933. He was transferred to the same post at the Court of Saint James in England in 1933.
Count László was twenty-eight years old, when he met Gladys Vanderbilt, the seventh and youngest child of Alice Claypoole Gwynne and Cornelius Vanderbilt II, the president and chairman of the New York Central Railroad. Gladys grew up in the family home on Fifth Avenue in New York City, and their summer "cottage," The Breakers in Newport, Rhode Island. They married on January 27, 1908, at her family home in New York City, after their meeting in Berlin near her twenty-first birthday in 1907. Their early married life was spent in Hungary raising their five children. Together, Count László Széchenyi and Gladys Moore Vanderbilt had:
Count László Szécheny died in Hungary in 1938.