He was named in football to All-Ohio Capital Conference, All-Central District and to the Dispatch's All-Metro teams.

Elflein also excelled on the track and field team; as an eighth grader, he won a division title in the shot put, and his best throw was 50 ft 11 in (15.52 m).

31 by Scout.com, Elflein didn't wrestle with his decision about which school to attend once he received a scholarship offer from the Ohio State University, committing on July 14, 2011.

As a redshirt freshman in 2013, Elflein earned his first varsity letter playing in all 14 games as a reserve offensive lineman when Corey Linsley was the Buckeyes' senior center.

His play against the Wolverines in the one-point win earned him the start in the Big Ten championship game against Michigan State.

Elflein earned the first of his three first-team All-Big Ten seasons as a sophomore, starting all 15 games including the 2015 College Football Playoff National Championship.

In his junior campaign, Elflein started all 13 games at the right guard spot for a Buckeye squad that finished 12-1 and capped their season with a 44–28 win over Notre Dame in the Fiesta Bowl.

[6] He was also named first-team All-Big Ten Conference for the second consecutive year by the league's head coaches and also by the media as he helped pave the way for Ohio State to lead the Big Ten in rushing at 245.2 yards per game and finish second in the conference in scoring and third in total offense.

[7][8] He ended up garnering the Rimington Trophy as the nation's top center and helping Ohio State make the College Football Playoff semifinals.

Elflein also was one of three finalists for the Outland Trophy and won the Pace Big Ten Offensive Linemen of the Year.

Along with Malik Hooker, they became the first pair of Buckeye teammates to be named unanimous All-Americans in the same year since Orlando Pace and Eddie George back in 1995.

[10] Following his senior season, in which he had transitioned to center, an NFC West scout declared to NFL.com: "In Elflein, you are getting a guy who will be great for your locker room and will get the rest of the offensive line on board.

[25] Elflein started the final six games of the season for the Jets at left guard after Alex Lewis was injured.