McConkie was born on July 29, 1915 in Ann Arbor, Michigan to Oscar Walter McConkie and Margarat Vivian Redd. Before he was a year old, his family moved to Monticello, Utah. From 1920-1923 Oscar McConkie served as the bishop of the Monticello Ward of The Church of Jesus Christ of Latter-day Saints. In 1925 his family moved back to Ann Arbor where his father continued studying law, then in 1926 they moved to Salt Lake City, Utah. McConkie attended Bryant Junior High School and LDS High School, where he graduated at age 15. He attended three years of college at the University of Utah before serving a Church mission. He grew to stand 6'5" tall.

McConkie would inherit his father's preaching style and doctrinal views, though he differed from his father politically, as McConkie was a Republican and his father was a noted Democrat.

On September 6, 1934, McConkie received a call to serve in the Eastern States Mission under President Don B. Colton. His first assignment was in Pittsburgh, Pennsylvania. From May 1 to July 24, 1935, he served in the Cumorah District in Palmyra, New York as part of an intensive missionary campaign tied to the dedication of a monument to Moroni on the Hill Cumorah. McConkie then served in the Seneca District and later presided over that same district.

In 1936 McConkie participated in the first Hill Cumorah Pageant which was attended by his future father-in-law, Joseph Fielding Smith. At the end of his second year of missionary service, McConkie "extended his mission for six weeks to travel, without a companion, from town to town throughout the mission, teaching investigators and missionaries" at the request of his mission president.

McConkie met Amelia Smith, daughter of apostle Joseph Fielding Smith, before his mission while attending the University of Utah. He and Amelia graduated from that institution in June 1937, he with a Bachelor of Arts degree and she with a bachelor's degree in bacteriology and pathology. They were married in the Salt Lake Temple by Amelia's father on October 13, 1937. Together they had nine children: Bruce (1938), Vivian (1940), Joseph (1941), Stanford (1944), Mary (1946), Mark (1948), Rebecca (1950), Stephen (1951), and Sara (1957). Their oldest child, Bruce, lived less than two months.

McConkie graduated with his Bachelor of Laws degree in 1939 and ranked third out of seventy-five on the bar exam. His degree was automatically upgraded to Juris Doctor in June 1967. Following his graduation, McConkie worked as assistant city attorney in Salt Lake City.

McConkie enrolled in Army ROTC while at the University of Utah. With the advent of World War II, he was called to active duty service on March 5, 1942. He served in military intelligence at Fort Douglas for the duration of the war and received the American Campaign Medal and the World War II Victory Medal. He held the rank of Lieutenant Colonel at his discharge on February 26, 1946, one of the youngest in Army Intelligence to hold that rank.

McConkie worked for a time as a reporter for the Deseret News. While covering the proceedings of General Conference on October 6, 1946, McConkie was interviewed by Apostle David O. McKay to fill a vacancy in the First Council of the Seventy created by the death of John H. Taylor. McConkie's name was presented for a sustaining vote by the membership of the church that same day and on October 10, he was ordained and set apart by Church President George Albert Smith. He served as a member of the First Council of the Seventy for twenty-six years.

On June 11, 1961, McConkie was ordained a high priest by First Presidency member Henry D. Moyle. This was in accordance with a new policy requiring the First Seven Presidents of Seventy to assist the Twelve in setting apart stake presidents, stake high councilors, and bishops.

In 1958 McConkie published a book entitled Mormon Doctrine: A Compendium of the Gospel, which he described as "the first major attempt to digest, explain, and analyze all of the important doctrines of the kingdom" and "the first extensive compendium of the whole gospel...the first attempt to publish an encyclopedic commentary covering the whole field of revealed religion." He included a disclaimer that he alone was responsible for the doctrinal and scriptural interpretations, a practice unusual at the time.

In writing the book, McConkie relied heavily upon the scriptures and recognized doctrinal authorities. Church leaders were surprised by its publication (since he had not asked permission and was not asked to develop such a work) and responded that while they applauded the attempt of the book to fill a need, it used a harsh tone and, in the words of Mark E. Petersen, was "full of errors and misstatements, and it is most unfortunate that it has received such wide circulation." Church president David O. McKay asked McConkie not to reprint, but later McConkie was asked to revise it with the editorial help of Spencer W. Kimball. The 1966 second edition incorporated many changes, especially a softening of the tone.

Much of the Bible Dictionary included with the LDS Church's publication of the Bible in 1979 borrows from Mormon Doctrine.

McConkie received a call from the First Presidency to preside over the Southern Australian Mission of the Church, which encompassed all of western and southern Australia, on February 9, 1961. He disclosed the call to his wife, Amelia, only after a hike up Ensign Peak that same day. Their daughter, Vivian, was married and Joseph was serving a mission to Scotland, so six of their children accompanied them to Australia.

In October 1962, McConkie reported "an all-time high mark in mission converts and willingness of members to build new chapels. ... There has been no difficulty getting six building missionaries to work on each chapel under the supervision of supervisors called from the states."

The mission decided upon a motto of "Seek the Spirit" and President McConkie taught the missionaries what it is to be humble and hear the whisperings of the Spirit.

McConkie resumed his duties as a Seventy after returning in 1964.

President Joseph Fielding Smith (who was McConkie's father-in-law) died on July 2, 1972. The First Presidency was subsequently reorganized with Harold B. Lee as President, leaving a vacancy in the Quorum of the Twelve Apostles . In October 1972, McConkie was invited to Lee's office "where President Lee put his arms around him by way of greeting and said, 'The Lord and the Brethren have just called you to fill the vacancy in the Council of the Twelve.' Bruce responded, 'I know. This is no surprise to me. I have known it for some time.'"

McConkie served in the capacity of an Apostle until his death in 1985, aged 69.

McConkie wrote several poems, a few of which he read in various general conference addresses. One for which he is especially remembered is the poem I Believe in Christ, delivered in a 1972 General Conference address, "The Testimony of Jesus". It was later set to music and published in the LDS Hymnal, as Hymn #134, "I Believe in Christ" and has since gained popularity among members of the church.

McConkie also penned the fourth verse to Hymn #21, "Come, Listen to a Prophet's Voice".

McConkie gave several influential general conference addresses. Prominent among them was his last conference talk in 1985, " The Purifying Power of Gethsemane." He concluded this talk with a poignant testimony of Jesus Christ:

McConkie died less than two weeks later.

McConkie's works in general are characterized by their authoritative tone. McConkie once wrote to a Mormon scholar in 1980, "It is my province to teach to the Church what the doctrine is. It is your province to echo what I say or to remain silent." In his best selling Doctrinal New Testament Commentaries and Messiah series, the sources that are most frequently cited as authority for his interpretational positions are other works authored by himself. He explained, "I would never quote another man unless I could first square what he said with the scriptures and unless he said what was involved better than I could."

One of the most controversial topics that McConkie defended in his writings was the church's policy of limiting the priesthood to men of non-African descent until 1978. This policy was known informally as the "Negro doctrine." His basis for this defense was that, in his view, those of African descent had been less valiant in the pre-existent life that the LDS believe was a precursor to life on earth. In 1958, McConkie wrote:

In the pre-existent eternity various degrees of valiance and devotion to the truth were exhibited by different groups of our Father's spirit offspring. One-third of the spirit hosts of heaven came out in open rebellion and were cast out without bodies, becoming the devil and his angels. The other two-thirds stood affirmatively for Christ: there were no neutrals. To stand neutral in the midst of war is a philosophical impossibility.

Of the two-thirds who followed Christ, however, some were more valiant than others. Those who were less valiant in pre-existence and who thereby had certain spiritual restrictions imposed upon them during mortality are known to us as the negroes.

Negroes in this life are denied the priesthood; under no circumstances can they hold this delegation of authority from the Almighty.

The present status of the negro rests purely and simply on the foundation of pre-existence. Along with all races and peoples he is receiving here what he merits as a result of the long pre-mortal probation in the presence of the Lord. The principle is the same as will apply when all men are judged according to their mortal works and are awarded varying statuses in the life hereafter.

On June 1, 1978, McConkie was present in the Salt Lake Temple when a revelation was received by the First Presidency and the Twelve "that the time had now come to extend the gospel and all its blessings and all its obligations, including the priesthood and the blessings of the house of the Lord, to those of every nation, culture and race, including the black race." This revelation was announced to the world on June 8, 1978.

McConkie's earlier statements on the topic, like those of other other church leaders, implied or overtly stated that the priesthood restriction would never be lifted. To this, McConkie stated:

There are statements in our literature by the early Brethren that we have interpreted to mean that the Negroes would not receive the priesthood in mortality. I have said the same things, and people write me letters and say, "You said such and such, and how is it now that we do such and such?" All I can say is that it is time disbelieving people repented and got in line and believed in a living, modern prophet. Forget everything that I have said, or what President Brigham Young or George Q. Cannon or whoever has said in days past that is contrary to the present revelation. We spoke with a limited understanding and without the light and knowledge that now has come into the world.

It doesn't make a particle of difference what anybody ever said about the Negro matter before the first day of June 1978. It is a new day and a new arrangement, and the Lord has now given the revelation that sheds light out into the world on this subject. As to any slivers of light or any particles of darkness of the past, we forget about them. We now do what meridian Israel did when the Lord said the gospel should go to the Gentiles. We forget all the statements that limited the gospel to the house of Israel, and we start going to the Gentiles.

McConkie also made controversial comments about Jews in his book “The Millennial Messiah”:

Let this fact be engraved in the eternal records with a pen of steel: the Jews were cursed, and smitten, and cursed anew, because they rejected the gospel, cast out their Messiah, and crucified their King.

He then goes on to blame the Jews' rejection of Jesus as the cause of historical persecution of the Jews:

Let the spiritually illiterate suppose what they may, it was the Jewish denial and rejection of the Holy One of Israel, whom their fathers worshiped in the beauty of holiness, that has made them a hiss and a byword in all nations and that has taken millions of their fair sons and daughters to untimely graves.

• Doctrines of Salvation, by President Joseph Fielding Smith, compiled by Bruce R McConkie: Volume 1, 1954; Volume 2, 1955; Volume 3, 1956.
• Mormon Doctrine, A Compendium of the Gospel, 1958.
• Mormon Doctrine, Second Edition, 1966.
• Doctrinal New Testament Commentary: Volume 1, The Gospels, 1965. Volume 2, Acts—Philippians, 1970. Volume 3, Colossians—Revelation, 1972.
• The Messiah Series, six-volume set that includes the following three Messiah titles
• The Promised Messiah, 1978.
• The Mortal Messiah, four volumes, 1979-1981.
• The Millennial Messiah, 1982.
• A New Witness for the Articles of Faith, 1985

McConkie also wrote numerous articles for the Church News and church magazines, handbooks, pamphlets, and manuals. He wrote the chapter headings for all chapters in the church-published standard works and contributed to the Bible Dictionary.