Young was born in London, the son of John Tonkin Young, a builder from Veryan, Cornwall. He was educated at the Communal College of Boulogne, under Professor Opel at Wiesbaden, in 1842 at the College for Civil Engineers in Putney, and at King's College London from 1843 to 1845, where John Howard Clark was a fellow student. Another reference says this fellow-student was Howard Clark's brother A. Sidney Clark. He worked in Cornwall on railway and mining construction then left for Adelaide in 1850. on the ship Panama, arriving on 31 October 1850. A fellow passenger was W. W. R. Whitridge, with whom he was to strike a lasting friendship. He joined the rush to the Victorian goldfields but soon returned. In 1851 he became second master at the newly established South Australian High School, but the venture failed by the end of the year. Headmaster Charles Gregory Feinaigle, before 1860 spelled "Feinagle", opened a private academy at his residence Brandon on Unley Road, but was soon in Victoria, in a wide variety of vocations. He remained friends with J. L. Young: together they founded the Philosophical Society in January 1853, along with Whitridge, who by this time was editor of The Register, and he maintained active membership after he left Adelaide. In December 1851 Young departed Adelaide via the overland route and the Victorian Goldfields at Mt Alexander. On 23 February 1852 Young Returned to Adelaide on board the Elizabeth. Young returned to the goldfields aboard the brig Louisa on 8 March and on 30 July arrived back in Adelaide aboard the Reliance. A letter later appears in the Register signed by Young and some passengers referring to 'mutinous conduct' by the crew and commending the efforts of the captain of the ship. After the South Australian High School folded, he was persuaded in 1852 to open his own school at the rear of the old chapel in Ebenezer Street off Rundle Street East, and soon moved to larger premises in Stephens Place. His brother, Oliver Young, held classes for some time, but returned to Cornwall in 1866. Oliver never married. On 29 October 1855, John married first cousin Martha Paynter Young. Their children included:
first son Arago was born early in 1857 but died at Glenelg on 7 March 1859.
Bertha Young was born at Parkside, as were all succeeding children. She died in England.
Edith Young
Ellen Young died in England.
Abraham Lincoln Young
John Howard Young died in Otago, New Zealand. His will, dated 1924, by its omissions, indicates an antipathy to his father and siblings.
Emily Young
Roland Hill Young died in Perth, Western Australia. None of J. L. Young's children had an academic career.
In 1861 he built the large two-storey Young House in Parkside, which was used both as his private residence and as a student boarding house. He then commissioned architects Wright and Hamilton to design and oversee building of a schoolhouse next door.. In 1871 he was able to relinquish the Freeman Street premises. John retired in 1880 and closed the school, with the intention of joining his wife and large family who were visiting brother Oliver and his father in Veryan, in Cornwall. A testimonial was held 17 December 1880 by his old scholars, and he was presented with a purse of sovereigns. His 16-room residence, with schoolhouse and various other houses on Young Street, after several auction attempts in February 1881, was eventually purchased by Alfred Allen Simpson. The two Parkside buildings at 61–71 Young Street were sold by Alfred A., Fred N. and Violet Laura Simpson to Mr. C. O. A. Lapidge in 1922. "Young House" has since been demolished but the heritage-listed schoolhouse still stands. He embarked on the steamer John Elder in 1881 to visit England, his family having preceded him, but died on 26 July 1881 while crossing the Red Sea. He was buried at sea. Martha returned to Adelaide, at first living in Kent Town then settled in Glenelg. She died 6 April 1887 aged 57. Fred W. Sims, formerly Deputy Registrar of Companies in the Supreme Court, wrote in The Advertiser:
The Death of John Lorenzo Young
John Lorenzo Young died in 1881 during a sea voyage to Britain. A recollection of his death and burial appears in a collection of letters by Timothy Coop and Henry Exley, published in 1882. The letter reads as follows;
Recognition
Young Street, Parkside, on which his home and last schoolhouse were situated, was named for him.
The J. L. Young Scholarship for Political Economy and the J. L. Young Research Scholarship at the University of Adelaide were established by Adelaide Educational Institution Old Scholars, notably including J. H. Finlayson, in his memory.
