Korff was born July 4, 1914, in Novograd-Volynsk, Ukraine. He was the second child of Grand Rabbi Jacob Israel Korff and Gittel Goldman Korff. Korff's early life was marked with tragedy. In 1919, when Korff was only 5 years old, Jewish pogroms swept through Eastern Europe. Ukraine was not exempt, and the Korff family found themselves caught in the middle of one such pogrom in 1919. Korff's mother fled her home with an infant in her arms, and three young children following her. Gittel Korff did not survive the 1919 pogrom in Novograd-Volynsk. Young Baruch Korff witnessed her murder, and would forever label himself a coward for not attempting to save her. Korff wrote in his memoirs that "My life ever since has been a quest for redemption from that charge." His father was suspected of committing treason and fled to Poland. Korff later went to Poland as well to be with his father. There he began studying in yeshivas. Korff stayed in Poland for seven years; however, he left to celebrate his bar mitzvah. He emigrated to the United States in 1926.
Korff studied in the Yeshiva Ohr Torah, Yeshiva Torath Chaim, and the Yeshiva Rabbi Isaac Elchanan. In 1934 he was ordained a rabbi, following in the footsteps of his ancestors. He was part of an unbroken line of rabbis that went back 73 generations. He was the headmaster of the Yeshivah Torath Emeth in Brooklyn, New York from 1936 to 1937. He later became the rabbi for the Congregation Hayim Solomon from 1938 to 1940.
Korff became an adviser to the Union of Orthodox Rabbis of the U.S. and Canada. He was also an advisor to the U.S. War Refugee Board. He was also the director of the Emergency Committee to Save the Jewish People of Europe, and later became an active member of the Political Action Committee for Palestine. Korff was also a Zionist.
Korff was active in the anti-Nazi movement prior to and during World War II. Korff was the director of the Emergency Committee to Save the Jewish People during World War II. Korff was responsible for gathering over 1,000 rabbis in Washington D.C. to march in order for Britain to allow Jewish immigration after the war.
In 1947 in the aftermath of the Exodus incident, he led a Stern Gang plot to bomb London in protest. Korff traveled to Paris and offered a member of the United States Air Force, Reginald Gilbert, money to fly the plane that would bomb London. Gilbert accepted Korff's offer, and then took the matter to French police. Korff was then arrested. In protest of his arrest, he held a hunger strike which lasted 17 days until he was released by officials. Korff fell into a coma and was treated in a hospital, but all charges were dropped against him. Korff was also part of Menachem Begin's underground movement in the 1948 Palestine war.
In 1950, he became the rabbi of a Temple Israel located in Portsmouth, New Hampshire. He served in that capacity for three years until he worked as a rabbi in Taunton, Massachusetts, where he stayed from 1954 to 1971. During this time, Korff was also a chaplain at the Massachusetts Department of Mental Health. In his later years, Korff also appeared as a panelist on the Sunday-morning show Confluence.
Korff first met Nixon during his presidential campaign in 1967. Korff became an active supporter of Richard Nixon, despite Nixon's known anti-Semitism. He defended Nixon during Nixon's growing unpopularity over Watergate. In 1974, Korff had founded the National Committee for Fairness to the Presidency, the purpose of which was to reaffirm "Our faith in God and country, in Constitutional government, in the presidency, and in our beloved President." The committee made several newspaper ads that promoted Nixon as president. Korff even held a three-day event of fasting and prayer on Nixon's behalf, and was active in raising money to help with Nixon's growing legal expenses. Korff also met with Nixon on August 6, 1974 in order to convince him not to resign from office. Nixon later stated that Korff "spoke with the fire of an Old Testament prophet" when he tried to convince Nixon to fight to stay in office. The rabbi told Nixon that "You will be sinning against history if you allow the partisan cabal in Congress and the jackals in the media to force you from office." Even after the president was out of office, Korff continued to visit with him. He also established a trust fund to help pay off Nixon's legal fees, which totaled over $155,000. Korff retired from raising funds for Nixon in May 1975.
Many American Jews were embarrassed at Korff's behavior. However, he did receive support from Yitzhak Rabin and Golda Meir. Korff later admitted that what Nixon did in the Watergate Scandal was wrong, but continued to stand by him.
Korff met with Nixon on May 13, 1974, after which he wrote the book The Personal Nixon: Staying on the Summit. During spring of the same year, Nixon had referred to Korff as his rabbi.
Rabbi Baruch Korff married Naomi Ruth Sternburg on October 25, 1942. The couple had two children; however, they divorced in 1952. He was later married to Rebecca Marshall in the mid-1960s. Their only daughter is named Zamira. This second marriage also ended in divorce.
Rabbi Korff appears under the pseudonym of Rabbi B in Heidi Mattson's memoir Ivy League Stripper. Mattson accused "Rabbi B" of sexual assault..
Rabbi Korff was the uncle of Grand Rabbi Yitzhak Aharon Korff.
Korff moved to Providence, Rhode Island in 1983 taking a job position as a consultant at Brown University. He would go on to write three books: Flight from Fear, The President and I, and The Personal Nixon: Staying on the Summit. Korff died on July 26, 1995 due to pancreatic cancer.