Kessler – along with brother Boeli and cousins Tonny and Dé – played club football for amateur side HVV Den Haag.

"[6] His younger brother Jean Baptiste August "Guus" Kessler Jr., who had married Bep's cousin, Anna Francoise "Ans" Stoop, continued with the Royal Dutch and eventually rose to head their father's company.

[2] He was considered a very innovative manager, steering the company through the difficult economic environment of the Great Depression; he also believed it was necessary to provide fair wages and establish a pension plan—unusual for that time.

[9] Kessler would remain the director of Hoogovens until his death from a brain tumor in 1945, with a short break during the Second World War, when the Germans kept him hostage in camp Kamp Sint-Michielsgestel.

[2] Their home, known as Slingerduin or the Villa Kessler, was built and designed in 1929 by the prominent Dutch architect Hendrik Wouda (1885–1946), a follower of Frank Lloyd Wright.

[11][12] Kessler was an uncle of the Dutch diplomat and historian Max Kohnstamm (1914–2010), with whom he was interned at camp Beekvliet in Sint-Michielsgestel; they became quite close there despite the difference in age.

[14] In 2016, the Rijksmuseum published, as part of its Studies in Photography series, "Around the World in 87 Photographs: Dolph Kessler's Grand Tour, 1908," by Mickey Hoyle.