Jonkheer Johan George Reuchlin was born on 6 December 1874 in Rotterdam, Netherlands, to Otto Reuchlin, a wine merchant (b. 18 June 1842 in Rotterdam, d. 15 November 1924 in Rotterdam) and Carolina Helena Schumacher (b. 18 November 1848 in Rotterdam; d. 30 January 1897 in Rotterdam). His parents had married 27 April 1871 at Kralingen, Netherlands (Kralingen merged with Rotterdam in 1895).

Johan George had least two known sisters; Maria Catharina Geertruida, born 10 January 1872 at Rotterdam, and Carolina Helena, b. 5 October 1885 (d. 1885) and two known brothers, Maarten, born 5 January 1873 at Rotterdam, and David Fredrik, b. 22 August 1878 at Rotterdam.

By a royal decree dated 3 December 1880, the Reuchlin children were allowed to use the title "Jonkheer" (for the male children) or "Jonkvrouw" (for the female children), which suggests a noble heritage.  The Reuchlin family belonged to the Reformed/Calvinist Church.

Johan George Reuchlin’s mother died in 1897 and his father then married Catharina Maria Schumacher (Carolina's sister, i. e. Johan George’s aunt) 8 June 1899 at Rotterdam.

Johan George Reuchlin married Agatha Maria Elink Schuurman in Rotterdam on 10 May 1905. They had three children: Henri, b. 6 July 1906, Carolina Helena, b.5 July 1908, and Maarten, b. 3 February 1911. The family lived at 53, Calandstraat, in Rotterdam.  Johan George Reuchlin was 5’6’’ tall, had black hair and brown eyes.

He boarded the Titanic at Cherbourg as first class passenger carrying ticket number 19972. The ticket was complimentary because of his position with the Holland America Line which was part of the International Mercantile Marine, J. Pierpont Morgan's conglomerate that also owned the White Star Line.

Reuchlin was on the Titanic to evaluate the Olympic-class liners. The Holland America Line had ordered a large vessel from Harland & Wolff - the Statendam II which was already under construction in March 1912.

Bruce Ismay wrote a letter concerning Reuchlin's voyage on 21 March 1912 to the general director of the Holland Amerika Line:

Mr Reuchlin appears to have enjoyed the voyage. On April 14th he received and sent some telegrams:

(1) received from the Noordam at 2.25 pm
Mr Reuchlin 1st cabin passenger SS TITANIC
Had moderate wly. winds and fair weather no fog.
Wish you pleasant trip
Krol

(2) sent to Cape Race at 6.15 pm
Reuchlin Calandstraat 53 Rotterdam
Continuing smooth and fair Greetings

(3) sent to Caronia at 6.54 pm
Captain, Steamer Noordam
Thanks for message had fine weather no fog bon voyage
Reuchlin.

(4) received from Noordam via Caronia at 7.44 pm
Mr Reuchren (sic) 1st Cabins passenger SS Titanic
Had moderate westerly winds and fair weathe no fog wish you
pleasant trip
Krol

(5) sent to Noordam at 8.55 pm
Captain Steamer Noordam
Thanks for message had fine weather no fog bon voyage
Reuchlin.

Reuchlin died in the disaster apparently making no effort to save his own life. His family characterized him as a "very integer [sic] and good person, who did not insist on getting a seat in a lifeboat". On 18 April the director of the Holland Amerika Line in America, Mr C. Gips, awaited Mr Reuchlin at New York Harbour, not knowing that he had died in the sinking. The sad information was told to him by Bruce Ismay. Gips immediately sent a telegram to HAL, Rotterdam and a letter to Mr Reuchlins wife Agatha. She received a annual payment of hfl. 5000,-- from the Holland America Line.

Reuchlin's body, if recovered, was never identified.

His wife Agatha seems never to have remarried and passed away 18 August 1960 in Rotterdam, aged 80.