On March 17, 1886, Cannon was convicted under the Edmunds Act of unlawful cohabitation and sentenced to six months' imprisonment and a fine of $300.

[3] Despite this conviction, Cannon married his third and fourth wives—Mary E. C. Young on January 11, 1887, and Lilian Hamlin on June 17, 1896.

[6] In 1882, at the age of 23, Cannon assumed business control of the Juvenile Instructor and associated publications.

On October 7, 1889, church president Wilford Woodruff named Cannon a member of the Quorum of the Twelve Apostles.

He underwent at least one surgery to relieve pressure and drain the infection, but the illness continued.