James Longstreet first met his friend Ulysses Grant in 1843, during the Mexican war. Grant became acquainted with and courted Longstreet's fourth cousin, Julia Dent, and the couple eventually married. Longstreet attended Grant's wedding on August 22, 1848 in St. Louis, and Grant biographer Jean Edward Smith believes that Longstreet served as Grant's best man at the wedding, though other historians disagree.(Neither Grant nor Longstreet mentioned such a role in either of their memoirs.) Twenty years later, when Longstreet learned that his old friend Grant was in command of the Union Army, he told his fellow officers "Grant will fight us every day and every hour until the end of the war." When Longstreet retreated with Robert E. Lee in the Appomattox Campaign, he advised Lee of his belief that Grant would treat them fairly.
Shortly after the surrender was signed, Grant met with a few Southern officers. When he saw Longstreet in the group, he approached him warmly, grabbed his hand and said, “Pete, let us have another game of brag, to recall the days that were so pleasant.” Longstreet later reflected on how he felt at the time, writing: “Great God! I thought to myself, how my heart swells out to such magnanimous touch of humanity. Why do men fight who were born to be brothers?”
After the war, Longstreet and his family settled in New Orleans, where he entered into a cotton brokerage partnership. He applied for a pardon from President Andrew Johnson, and this was supported by his old friend Grant, who was then the Union Army General-in-Chief. Johnson refused the pardon, telling Longstreet in a meeting: "There are three persons of the South who can never receive amnesty: Mr. Davis, General Lee, and yourself. You have given the Union cause too much trouble."
Longstreet was one of a number of former Confederate generals, including James L. Alcorn and William Mahone, to join the nationally dominant Republican Party during the Reconstruction era. He endorsed Grant for president in the election of 1868, attended his inauguration ceremonies in Washington, D.C. and six days later was appointed by Grant as surveyor of customs in New Orleans. This cost him his reputation the the eyes of many white Southerners. His old friend Harvey Hill wrote to a newspaper: "Our scalawag is the local leper of the community."
Longstreet continued his friendship with Grant until Grant's death in 1885. He held a number of jobs in government. In 1880, President Rutherford Hayes appointed Longstreet as his ambassador to the Ottoman Empire and later he served from 1897 to 1904, under Presidents William McKinley and Theodore Roosevelt, as U.S. Commissioner of Railroads. He served as a U.S. Marshal from 1881 to 1884, but the return of a Democratic administration under Grover Cleveland ended his political career. In December of 1889 his wife Louise Longstreet died. But he surprised everyone in 1897 when, at the age of 76 in a ceremony at the governor's mansion in Atlanta he married 34 year old Helen Dortch. Helen became an supporter of his legacy after his death. She outlived him by 58 years, dying in 1962.
When Grant died in 1885, one of his pallbearers was former Confederate General Simon Bolivar Buckner. Buckner and Grant became friends at West Point and served together in the Mexican–American War. When Captain Ulysses S. Grant ran into trouble at a New York hotel due to a shortage of money, Buckner helped him out by covering his expenses until money arrived from Ohio to pay for his passage home. years later, in February of 1862, Union Brigadier. General Ulysses S. Grant captured Fort Henry on the Tennessee River. General Albert Sidney Johnston sent Buckner to be one of four brigadier generals defending Fort Donelson. When command was passed to Buckner, he sent a messenger to the Union Army requesting an armistice and a meeting of commissioners to work out surrender terms, hoping his old friend Grant would offer generous terms. Grant's famously replied "No terms except unconditional and immediate surrender can be accepted. I propose to move immediately upon your works." Buckner responded in part, "the overwhelming force under your command compels me to accept the ungenerous and unchivalrous terms which you propose." In spite of the tension in the correspondence, Buckner greeted his old friend warmly when Grant arrived to accept the surrender. They joked about their time in Mexico and Grant offered to loan Buckner money to see him through his impending imprisonment, but Buckner declined.
Buckner later not only acted as a pall bearer for Grant. He also paid for Grant's funeral and provided Grant's widow a financial monthly payment so she could live out her years.
General Joseph E. Johnston was also one of Grant's pallbearers. Though his postwar friendship with Grant was not as close as that of Longstreet and Buckner, Johnston never forgot the magnanimity of the man to whom he surrendered. He would not allow criticism of either Grant or of William Tecumseh Sherman in his presence. Johnston was closer to Sherman and the two corresponded frequently, and met for friendly dinners in Washington whenever Johnston traveled there. Johnston served as an honorary pallbearer at his Sherman's funeral.
There is a story about Johnston at Sherman's funeral. During the procession in New York City on February 19, 1891, he kept his hat off as a sign of respect for his former adversary. It was a cold and rainy day and someone concerned for his health asked Johnston to put on his hat. Johnston replied, "If I were in his place and he were standing here in mine, he would not put on his hat." He caught a cold that day, which developed into pneumonia and died several weeks later in Washington, D.C.
It is remarkable that despite the horrors of war that Grant and his confederate adversaries experienced, Grant retained the strength of character to leave the past in the past and to treat his former opponents with civility, respect and generosity. It sounds like the feeling was mutual.