Mr Julius Konrad Eugen Karlsson, 23, was born 29 September 1878 the son of Anders and Augusta Kristina Karlsson, Luntgatan 8, Norrköping, Östergötland, Sweden. His parents had married 30 October 1874. His brothers and sisters included Judit Cecilia Antonia, b. 1875, Jenny Celinda, b. 9 April 1884, Justus Erik Konstantin, b. 1888, and Julia Carolina Elisabet, b. 1900.

He married Adelaide Fredrika (nee Gran; born 27 May 1879 in Gothenburg) Karlsson on 18 February 1910.

Karlsson was an engineer and inventor, living, in 1912, at Annielund 5, Krokslätt, Gothenburg, Sweden. 

Julius Karlsson's father was a carpenter but did not have the money to fund his son's education and so Julius had to finance himself. He developed an interest in looms and studied in Finland for some years before taking a degree at Lenningska weaving school in Norrköping, Sweden. He then gained employment in a textile factory in Vejle, Denmark, and became a loom constructor inventing among other things an automatic shuttle changer.

In Gothenburg, he later worked for the Claes Johansson-Marks mechanic workshops. The trip to the USA was to arrange patent registrations, but he probably intended to settle there, because his wife later in a letter to the ministry of foreign affairs mentioned that she should have followed him in the autumn. Julius had a child outside of marriage, his name was Klas Julius Öjvind Hottsberg and he later lived in Oslo. The son was born while Julius had been in Denmark and was the result of a liaison with "shop assistant Alerine Margerethe Sørensen" according to the Danish ministry of foreign affairs.

Julius Karlsson boarded the Titanic at Southampton as a third class passenger. He died in the sinking, his body was never found.

The Mansion House Fund paid 1787.52 Kr (£100) to his wife, 875.32 Kr (£48) to parents and 1276.80 Kr (£70) to his mother in law. 5466 Kr (£300) in damage claims were paid on 28 August 1914 to the wife and parents. The wife got 2733 Kr, and because the parents were getting divorced the sum was further divided 1966.50 to father and 766.50 to the mother.

Julius and his wife had no children. His mother Augusta Karlsson divorced his father Anders Karlsson in 1914 and moved to a newbuilt cottage "Villa Titanic" Karlshof N:o 80, Östra Eneby, Norrköping (today Skördegatan 12). The house was partly built with the damage claims. An enamel sign on the wall read "Villa Titanic". The house has now been pulled down.