He was born in March 1885 as Gerrit Jongsma in Sloten, the farmost smallest of the eleven (elf) cities (steden) of the Dutch northern province Friesland, located in its southwestern lake district, the fourth of eleven children and third son of carpenter's hand (timmerknecht) Pier Willems Jongsma and Trijntje Dam.

Gerrit Jongsma had in Sloten the following ten siblings:
* Willem, 23 July 1879;
* Pieter, 13 April 1881;
* Fetje, 22 April 1883;
* Minne, 4 June 1887;
* Bauke, 12 September 1889;
* Foppe, 3 December 1891;
* Gijsbert, 20 May 1894;
* Auke, 27 May 1897;
* Sybrigje, 27 May 1897;
* Aukje, 23 October 1899.

On 4 January 1905 Gerrit's oldest brother W(illem) Jongsma (25 y, carpenter) arrived on the SS Statendam from Sloten at the port of New York, Ellis Island. His destination was the Dutch settlement Roseland, nowadays a southern district of Chigago, Cook County, Illinois, where his brother-in-law Siebold Heidmeyer was residing.
On 21 March 1906 Gerrit (21, carpenter) and his brother Minne Jongsma (19, carpenter too) arrived on the SS Rijndam from Sloten at the port of New York, Ellis Island. Their destination was Munster, Lake County, south of Chicago, in the utter northwestern part of Indiana, where their brother Willem Jongsma was already residing.
On 21 February 1907 his father Pier Jongsma (51, carpenter), his mother Trijntje (48), his siblings Fietje (23, servant), Bouke (17, carpenter), Foppe (15, cartwright), Gijsbert (12), Siebrickje (9) and Aukje (7) arrived from Sloten on the SS Noordam at the port of New York, Ellis Island. Their destination was Munster, Lake County, Indiana too, where their son and brother Willem Jongsma was already residing.
On 5 July 1910 Gerrit's brother Peter Jongsma (29), his wife Maatje (27), their children Kaatje (5), Maatje (3) and Peter (0) arrived on the SS Potsdam at the port of New York, Ellis Island. Their last residence place in the Netherlands was Idskenhuizen [Friesland, Netherlands] and they were heading for Hammond, Lake County, in the utter northwestern part of Indiana where the family of Peter's parents Pier and Trijntje Willems Jongsma was already residing.

Gerrit Jongsma married on 29 September 1909 in Lake County, Indiana to the three years younger Marie Kooy or Kooi, who had Dutch parents too.

In 1910 Garret Jongsma (25 y, born in Holland) and his wife Marie (22, Indiana) lived in North Township, Lake County, Indiana.

On 18 September 1914 Gerrit Jongsma was naturalized in Indiana.

On 12 September 1919 Gerrit P. Jongsma (33 y, shear man at Standard Steel Car Co.) lived in Hammond, Lake County, Indiana, when he was administrated on a World War I Draft Registration Card.

In 1920 Garret Jongsma (34), his wife Marie (32) and their son Eugene (1, Indiana) lived still in North Township, Lake County, Indiana.

In 1930 Gerrit Jongsma (45), his wife Mary (42), their children Eugene (12), Evelyn (9, Indiana) and James (1, Indiana) lived in Munster [North Township], Lake County, Indiana.

In 1935 and 1940 Garrett Jongsma lived in Munster, Lake County, Indiana too.

In 1942 Gerrit Jongsma (57, working at National Brick Co in Munster) resided at 8410 Columbia Ave in Munster, Lake County, when he was administrated on a World War II Draft Registration Card.

Gerrit Jongsma died in June 1964 at the age of 79 years in Hammond, Lake County, Indiana. His widow Mary died in March 1974 at the age of 86 years in Dyer, Lake County, Indiana.