Born in Honolulu, Hawaii of Samoan descent,[1] Seumalo and his family moved to Corvallis, Oregon during his early childhood.

Seumalo attended Corvallis High School, where he won 5A First-team All-State honors as an offensive and defensive lineman his junior and senior years.

Seumalo was particularly praised for his performance against reigning Pac-12 Defensive Lineman of the Year Star Lotulelei, in a victory over the Utah Utes.

[13] In 2017, Seumalo played in 14 games, however, he was benched as the starting left guard in favor of Stefan Wisniewski after a poor performance in a week 2 loss to the Kansas City Chiefs.

[14] Following the Super Bowl win, Seumalo entered the 2018 season as the backup left guard behind Stefen Wisniewski.

He made another post season appearance with the Eagles recording a win over the Chicago Bears before losing to the New Orleans Saints on January 13, 2019.

[20] On September 28, 2021, Seumalo was placed on injured reserve after suffering a Lisfranc injury in Week 3, ending his season after only appearing in three games.

[26] He recorded another postseason appearance when the Steelers lost 17-31 to the Buffalo Bills in the AFC Wild Card playoff game.

[29] Though only active for four games by the point of the Steelers' Week 9 bye, Seumalo took 96.25% of offensive snaps, did not allow a single quarterback hit or sack.

[31] Seumalo's father Joe is the defensive line coach at the University of Arizona, while his sister Jessi is the director of on-campus recruiting for the Washington State football team.