Eifert was the last of the 10 players drafted by the Bengals to sign with the team.
Terms of the contract were not disclosed by the team, but the Cincinnati Enquirer reported Eifert, who holds Notre Dame's record for receptions by a tight end (140), received a four-year contract expected to be worth $8.256 million.
"We've said all along that we expected Tyler's deal to get done in good time, but it's great to now have all our signings complete," coach Marvin Lewis said in a statement. "All 10 guys can help us by getting off to fast starts, and we are looking for Tyler to lead that. He's shown us everything we wanted to see in our offseason work."