Hamm, 44, will voice Grouper in the long-running Nickelodeon cartoon, inspired by his "Mad Men" character that finally netted the actor an Emmy, Don Draper, reported Variety.
The network also released a sketch of the character.
Grouper is described as "a charismatic head ad executive" with a "sharp mind and devastating charm."
Hamm's episode will see SpongeBob and Mr Krabs seeking business advice from Grouper in Krabs' endeavour to launch a line of frozen Krabby Patties.
The episode is preliminarily slated to air in 2016.