Roberta Wright and her identical twin sister Rowena (1912–2011) were born in Muskogee, Oklahoma on February 7, 1912. Her parents, Archibald Wright (1874–1971), a Los Angeles oil wildcatter, and Myrtle Mae Fletcher (1885–1972), were married in Cleburne, Texas, on June 18, 1901.
On January 21, 1933, she eloped to Tijuana, Mexico with a naval ensign, later to become four-star Admiral John S. McCain, Jr. in Caesar's Bar. She was attending the University of Southern California and McCain was attached to USS Oklahoma (BB-37). She became the daughter-in-law of Admiral John S. McCain, Sr., a noted World War II carrier admiral under Fleet Admiral William Halsey.
In 1952, she was the ship sponsor for USS John S. McCain (DL-3), named for her father-in-law. She was also an honored guest at the 1992 launching of USS John S. McCain (DDG-56) which was named for her husband and her father-in-law. She was also active in Navy Wives Clubs. For example, during Christmas 1971, she traveled to Saigon and presented $1,000 ($5,914 today) and 14 boxes of clothing to the Vietnam Advisory Board of Operation Helping Hand on behalf of the Pearl Harbor area Navy Wives Clubs.
Roberta McCain has three children: Jean Alexandra "Sandy" (McCain) Morgan (born 1934), John Sidney McCain III (born 1936), and Joseph Pinckney "Joe" McCain II (born 1942), twelve grandchildren and fifteen great-grandchildren.
As a Navy family, the couple moved around as the Navy required. Shortly after they were married, the McCains moved to Honolulu, Hawaii where her husband was stationed in 1933–1934, and where their daughter was born. They returned to Pearl Harbor in 1968 from the Admiral's post in London as commander of US European Naval Forces where they lived at the time of their son's capture in Vietnam.
It was in Pearl Harbor that the couple awaited the release of their son from captivity. In June 1968, Roberta McCain told Parade magazine, "Religion has been of great importance to us in our concern for Johnny, religion and the military tradition of my husband's family. We all pray for the time when we'll see Johnny again."
In 1971, she requested no special sympathy for her in regards to her son's captivity. She said navy tradition was important in the family, her daughter married a naval officer, John McCain III became a naval aviator and her youngest son Joe enlisted in the Navy during the Vietnam war. Her son John was held as a prisoner of war in North Vietnam for five and a half years. When notified upon his release on March 15, 1973, that he had shouted expletives at his captors, Mrs. McCain's response was, "Johnny, I'm going to come over there and wash your mouth out with soap."
John McCain has said of his mother: "My mother was raised to be a strong, determined woman who thoroughly enjoyed life, and always tried to make the most of her opportunities. She was encouraged to accept, graciously and with good humor, the responsibilities and sacrifices her choices have required of her. I am grateful to her for the strengths she taught me by example."
McCain campaigned during her son's 2008 presidential campaign, and was active in 2007 and 2008 despite her advanced age. In November 2007, her comments about Mitt Romney, his role in organizing the 2002 Winter Olympics and Mormonism during an MSNBC interview generated minor political controversy and forced her son to respond to clarify her remarks. In August 2008, she had a fashion shoot and was featured in a pair of Vogue magazine articles. On May 13, 2009, she appeared on The Tonight Show with Jay Leno. Her comments about Rush Limbaugh and Keith Olbermann created a stir with politicos on both sides even after her son's failed presidential bid.
McCain's life of traveling with family, specifically her twin sister, was noted by Maureen Orth in The New York Times in December 2007. On October 22, 2009, she was hospitalized while traveling in Portugal after she fell and injured her head.
Her 100th birthday in February 2012 was noted in a number of periodicals in the United States, including an article by Pulitzer Prize–winning journalist Ken Herman. She was featured in Town & Country magazine later that year.
In September 2013, television commentator Greta Van Susteren wrote about McCain in an essay that was featured by Politico during their series "Women Rule" which sought to explore "how women are leading change in politics, policy and their communities."