He entered the United States Postal Service as a clerk in Pittsburgh, Pennsylvania, on the advice of his uncle Bob Burke, a mail carrier, who encouraged young Patrick to take the postal service exam.

[3][4][5][6] His predecessor, Postmaster General John E. Potter, testified before the Senate[7] that if the Postal Service is not able to readjust their payment toward the pre-funding of retiree health benefits, as mandated by the Postal Accountability and Enhancement Act of 2006,[8] the USPS would be forced to consider cutting delivery to five days per week during the summer months of June, July, and August.

On February 6, 2013, Donahoe announced that the Postal Service would implement five-day mail delivery beginning August 5, a move he claimed would save $2 billion annually.

[9] July 16, the House passed the Financial Services and General Government Appropriations bill, which included language protecting six‐day mail delivery, thereby blocking Donahoe's plan.

[14][15] After his retirement from the Postal Service, Donahoe now serves on the board of SG360°, a marketing firm.