Monson was aged only 36 when ordained an Apostle in 1963, which made him the youngest Apostle since 1910. He had already had a record of holding Church positions at remarkably young ages, a ward bishop at 22 and mission president at 32.
Given the LDS Church tradition of the senior living Apostle succeeding as Church President, this has led to speculation that he would become a remarkably young Church President in turn . . . even now at age 76 he would be youngest since Harold B. Lee died in 1973.
On the death of Church President Spencer W. Kimball in 1985, Monson was chosen as Second Counselor in the First Presidency by new Church President Ezra Taft Benson . . . at age 58 the youngest Counselor since 1901. Serving in this position under Benson and Howard W. Hunter, he was named First Counselor on Hinckley's accession in 1995, simultaneously becoming President of the Twelve by seniority.