From a history found on familysearch.org, written by Dalbert Ray Chipman of American Fork, Utah:
John Greenleaf Holman, one of the original Utah Pioneers of 1847, an active and faithful elder in the LDS Church. He was born in Byron Center, Genesee, New York, October 18, 1828, the son of Joshua Sawyer Holman and Rebecca Greenleaf. He was baptized into the church when eight years old and moved with his parents to Kirtland, Ohio. The family moved to Nauvoo and later started for the West. In the spring of 1847, at Winter Quarters, Nebraska, he was chosen as one of the 143 pioneers who accompanied Brigham Young on the pioneer trek to Salt Lake Valley. He returned to the East in the fall of 1847, where he remained until the spring of 1850.
On August 23, 1849 he married Nancy Clark, who was born in Marion County, Indiana on February 26, 1826, a daughter of Richard Clark and Ann Elizabeth Sheffer. She bore her husband ten children: John Dennis, Artemus, Nancy Elizabeth, John Clark, Rebecca, Maria Josephine, Clarinda, Benjamin Franklin, & Lewis Clark. John Dennis died November 8, 1851.
Mr. Holman with his first wife and others, started for Utah in the spring of 1850, arriving in the later part of August of the same year. Soon after arriving in the Salt Lake Valley they started south to find a place to make a home. After looking all over the North of Utah County, they decided to settle in what is now called Pleasant Grove. And so on the day of September 13, 1850, Mr. Holman and six other families stopped in the grove of trees on the Battle Creek Canyon stream and began building of what is now Pleasant Grove. In 1851 he helped to make the McArthur Ditch which was the first ditch made from the American Fork River. In 1852 he with George S. Clark and a few others laid out and made a ditch from the mouth of American Fork Canyon to Pleasant Grove. He was a captain of a company in the Echo Canyon campaign against Johnston's Army. He was in the trouble with the Indians during the 1850's but usually made friends with them and many Indians always called on him when they passed through Pleasant Grove and considered him their good friend. He was Indian interpreter for this area. They nicknamed him "Mopage".
He married Rachel Stevens February 3, 1856. She was born December 1, 1834, a daughter of William Stevens and Marintha Thomas, in Upper Canada. She bore him seven sons and daughters: Rachel Marinda, Chastina, Joshua Stevens, Ordell, William Roy, Sarah Ellen and Elnora.
John G. Holman was a member of the Pleasant Grove City Council from 1855 to 1862 and served as counselor to Bishop Hansen Walker of the Pleasant Grove Ward from 1853 to 1862 when he was called to go on a mission to England. He returned to Utah in 1865. In 1866 he served as captain of the last ox train that crossed the plains making the seventh time that he crossed the plains with ox teams.
In 1875 he married Sarah Loader Harris, the daughter of James Loader and Amy Britnell. They were married on September 26, 1875. She bore her husband four children: Zilpha Ann, Emma Jane, Albert Loader and Ezekiel Loader. He moved to Santaquin, Utah in 1878. Here he resided for several years. In 1883 he moved to Rexburg, Idaho, where he died November 5, 1888.

Regarding the Mormon Battalion medal on John's gravesite:
From history.churchofjesuschrist.org - Joined Mormon Battalion Company C on July 16, 1846 and service ended August 6, 1846. Enlisted on the muster roll for Company C, but not included on subsequent military rosters and rolls. Likely did not march.