Henry Edward Gardiner was born on June 30, 1905 in Bozeman, Montana to Henry Cook Gardiner and Carrie Pierce Gardiner (née Gardner). In 1879, Carrie Gardiner’s parents, Edward Morgan Gardner and Florinda Gardner (née McCreary), traveled from Missouri to Bozeman, where they raised cattle. Carrie Gardner married veterinary surgeon Henry C. Gardiner in 1904 and together the couple had three children: Henry E. Gardiner, Elizabeth Soper (née Gardiner, 1908-1995) and Alice Sowerwine (née Gardiner, 1911-1997). Henry C. Gardiner moved the family to Anaconda in 1911, where he worked for the Anaconda Company following the Deer Lodge Valley "smoke case" (Bliss v. Anaconda Copper Mining Co., 1909). Henry E. Gardiner attended Anaconda High School and later Montana State College (now Montana State University) where he graduated in 1928. Following his graduation, he attended Cornell Law School in Ithica, New York, graduating in 1931. He returned to Montana where he worked for the Anaconda Company in Butte, Montana from 1932 to 1934, originally working without a salary. He was transferred to the Chicago office following a nearly five month long labor strike in Butte in 1934 that involved all the mine-mill and craft unions working for the Anaconda Company in Anaconda, Butte, and Great Falls. In Chicago, Gardiner worked as house counsel.

While in Chicago, Gardiner joined the Chicago Black Horse squadron, a special unit of the Illinois National Guard. He served in the U.S. Army during World War II, participating in the North African (Tunisia) and Italian campaigns. In 1943, he attained the rank of lieutenant colonel. For his service, he was awarded the Distinguished Service Cross, Silver Star, three Bronze Stars, two Purple Hearts, among others. Gardiner worked in the New York Anaconda office following World War II and, in 1945, he married Rita Singstad (1918-1975). Gardiner accepted a position to work in Anaconda Company’s Chilean office in 1948. He and his family moved to Santiago and lived there until 1964, after which they returned to the United States. Gardiner then worked in Washington D.C.'s Anaconda office until his retirement in 1974. In 1978, three years after his wife’s death in 1975, Gardiner moved back to Bozeman, Montana. In 1982, he was awarded an honorary doctorate from Montana State University. Henry Gardiner died on May 4, 1994, in Bozeman, Montana and was cremated.