John Orren Grettenberger was the son of German immigrants, George Jakob (1839-1897) and Katherine Elizabeth (Helwig) (1844-1918) Grettenberger. Born 28 May 1868, Okemos, Meridian Township, Ingham County, Michigan, John was oldest of 4 children born into an industrious, hard working farm family. John was enrolled in 1888 in the Okemos Union School and would go on to further his education with 2 years of high school instruction.

On 3 May 1894, Okemos, John married a class mate from the Okemos Union School, Wilhelmina C. "Minnie" Kaiser. Minnie too was born in Ingham County and had a German heritiage. John, although he farmed, was intent on owing and running a general store. By 1902 his establishment was well stocked with merchandizing notions but was almost wiped out of the entire store's line of homegoods in a daring night time robbery. John business recovered and he continued on to not only with his general store but to farm and in 1913 was appointmented Postmaster in Okemos. Both John and Minnie were involved and members of area clubs and lodges. They too were mainstays at the every growing yearly Grettenberger family reunions held in Ingham County.

According to the 1909-1910 Michigan State Gazetter and Business Dierctory, published by R. L. Polk & Company, "Okemos, Population, 400. On the P.M.R.R. and Red Cedar river, in Meridian township, Ingham county, 10 miles north of Mason, the county set, and 6 1/2 from Lansing the banking point. Has Baptist and Methodist Espiscopal churches, Telephone connection. Tel., W.U Expr., U.S.O. Hansberger, postmaster.

John and Minnie had 3 children. According to Minnie's 1958 obiturary, John ran his store, which eventually went from general merchandise to a grocery and drug store, from about 1885 until he retired in 1930. John succumbed to a heart attack 17 March 1944, Okemos. Minnie, born 5 May 1971 died 24 January 1958. John and Minnie were interred Glendale Cemetery, Okemos.

Grettenberger, John Orren (married Wilhelmina Kaiser 1894) general store robbery, The Lansing Journal, 12 June 1902 

Grettenberger, John Orin (married Minnie Kaiser 1894) family reunion, Lansing State Journal, 3 July 1918, Page 5

Grettenberger, John O. (married Wilhelmina Minnie Kaiser 1894) obit, Lansing State Journal, Saturday, March 18, 1944

Grettenberger, John O. (married Wilhelmina Minnie Kaiser 1894) Michigan Certificate of Death 1944