Considered only a three-star recruit by Rivals.com, he chose to attend Notre Dame over other offers from Indiana, Minnesota, and Purdue.

[8] He broke the school's tight end single-season receptions and receiving yards record, previously held by Ken MacAfee.

[10] After a 42–14 loss to the Alabama Crimson Tide in the 2013 BCS National Championship Game, Eifert decided to forgo his final season of eligibility and declared his intention to enter the 2013 NFL draft.

[16] On September 8, 2013, Eifert made his NFL debut, recording five receptions for 47 yards in a 24–21 loss to the Chicago Bears.

[18] On October 20, Eifert caught his first career touchdown on a 32-yard pass from Andy Dalton against the Detroit Lions.

[23] On September 7, 2014, during the first game of the 2014 season against the Baltimore Ravens, Eifert recorded three receptions for 37 yards before suffering a dislocated elbow and shoulder labrum tear after landing awkwardly on his arm while trying to twist out of a leg tackle.

[25] On September 13, 2015, Eifert posted a career day with nine receptions for 104 yards and two touchdowns in the season-opening victory over the Oakland Raiders.

[26] On October 11, Eifert was Andy Dalton's biggest target in a Week 5, 27–24 comeback victory against the two-time defending NFC Champion Seattle Seahawks with eight receptions for 90 yards and two touchdowns.

[32] On January 3, 2016, Eifert capped off the regular season with a touchdown in the Bengals' 24–16 win over the Baltimore Ravens.

[34] Eifert earned a bid to the 2016 Pro Bowl on Team Irvin but injured his ankle during the game.

[47] Eifert's 2017 season was again cut short due to injuries as he played in two games and had four receptions for 46 receiving yards.

[48] On October 11, 2017, the Bengals announced that Eifert would undergo back surgery for the second consecutive season, putting him out for the rest of the year.

[52] During a Week 4 matchup against the Atlanta Falcons, Eifert was carted off the field in the second quarter with a right ankle injury.

The following day, it was revealed that Eifert suffered a broken ankle and would undergo corrective surgery, missing the remainder of the season.