Smith-Njigba played in seven games as a freshman and led Ohio State's freshmen with 10 receptions for 49 yards and one touchdown.[11]
He was named a starter at the slot receiver position for the Buckeyes going into his sophomore season.[12] On November 6, 2021, Smith-Njigba recorded 15 receptions (single game school record) for 240 yards (the second most receiving yards in a game in school history at the time) and one touchdown in a 26–17 win against Nebraska.[13] Later that season, he set both an Ohio State single game and FBS Bowl record for receiving yards with 347 in Ohio State's win in the 2022 Rose Bowl.[14] In that game, he also recorded 15 receptions (tying his own record set in the aforementioned Nebraska game) and passed David Boston for the single season receiving yards record at Ohio State with 1,606.[15]
Smith-Njigba was limited to just three games in 2022 due to a hamstring injury and his decision to not participate in the College Football Playoff.[16] In addition, Smith-Njigba announced that he would pass on from his senior year of college and enter the 2023 NFL draft.[17]
Smith-Njigba was selected by the Seattle Seahawks in the first round (20th overall) of the 2023 NFL Draft.[20]
He caught his first regular-season NFL pass Week 1 against the Los Angeles Rams with a one-yard completion from Geno Smith.[21] Smith-Njigba started his first game Week 7 of that year after starter DK Metcalf was sidelined due to a rib injury;[22] during that game, he caught his first career touchdown pass on a 28-yard pass from Smith.[23] On October 29, Smith-Njigba caught the game winning touchdown pass from Smith on screen pass against the Cleveland Browns.[24] On December 18, Smith-Njigba caught the game winning touchdown pass from Drew Lock on Monday Night Football against the Philadelphia Eagles.[25] As a rookie, he appeared in all 17 games and made three starts. He finished with 63 receptions for 628 receiving yards and four receiving touchdowns.[26]
In the 2024 season during the week 9 game against the Los Angeles Rams, Smith-Njigba recorded a career high game with 7 catches for 180 yards and two touchdowns.[27]
Smith-Njigba is of half Sierra Leonean descent, and wears the country’s flag on the back of his helmet.[28] His paternal grandparents are from Sierra Leone.[29]
Smith-Njigba's older brother, Canaan Smith-Njigba, is a professional baseball player who is currently a free agent.[30]