San Francisco 49ers
Juszczyk entered free agency for the first time in his career in 2017 and was the top fullback on the market. He received interest and offers from multiple teams, including the Philadelphia Eagles, Browns, Bills, and the San Francisco 49ers. The Eagles were the top team to possibly land the prized free agent at first, but the Bills overtook them as the favorite, as they were looking for a stable replacement for Jerome Felton.
On March 9, 2017, the 49ers signed Juszczyk to a four-year, $21 million contract that included $7 million guaranteed and a signing bonus of $5 million. It was the largest contract for a fullback in NFL history.
In his 49ers debut, Juszczyk had two receptions for 17 yards in the season-opening 23–3 loss to the Carolina Panthers. On December 19, 2017, he was named to his second Pro Bowl.
Juszczyk finished his first season with the 49ers tallying 33 receptions for 315 yards and a touchdown to go along with 31 rushing yards.
In the 2018 season opener against the Minnesota Vikings, Juszczyk recorded a 56-yard reception in the 24–16 loss. During Week 3 against the Kansas City Chiefs, he scored his first touchdown of the season on a 35-yard pass from Jimmy Garoppolo. Juszczyk was named to his third Pro Bowl for his accomplishments in the 2018 season.
Juszczyk finished the 2018 season with 30 receptions for 324 yards and a touchdown along with 30 rushing yards.
In the 2019 season, Juszczyk appeared in 12 games and recorded 20 receptions for 239 yards and a touchdown. He was named to his fourth Pro Bowl.
During Super Bowl LIV against the Chiefs, Juszczyk caught three passes for 39 yards and a touchdown in the 31–20 loss. His touchdown reception in the game was the first by a Harvard alumnus in Super Bowl history, and the first by a fullback since Mike Alstott in Super Bowl XXXVII.
During Week 16 against the Arizona Cardinals, Juszczyk recorded two receiving touchdowns in the 20–12 road victory. He finished the 2020 season with 19 receptions for 202 yards and four touchdowns to go along with 17 carries for 64 yards and two touchdowns. For the fifth consecutive season, Juszczyk was named to the Pro Bowl. He was ranked 97th by his fellow players on the NFL Top 100 Players of 2021.
On March 15, 2021, Juszczyk signed a five-year contract extension with the 49ers worth $27 million. He recorded 30 receptions for 296 yards and a touchdown to go along with a rushing touchdown in the 2021 season. For the sixth consecutive season, Juszczyk earned a Pro Bowl nomination. He was ranked 100th by his fellow players on the NFL Top 100 Players of 2022.
During the 2022 season, Juszczyk recorded 19 receptions for 200 yards and a touchdown, as well as seven carries for 26 yards and a touchdown. For the seventh consecutive season, he earned a Pro Bowl nomination.
In the 2023 season, Juszczyk appeared in all 17 games and started 16. He finished with 14 receptions for 119 yards and two touchdowns. He earned first team All-Pro honors and an eighth Pro Bowl nomination. Juszczyk appeared in Super Bowl LVIII against the Chiefs and recorded two receptions for 31 yards in the 25–22 overtime loss.
In the 2024 season, Juszczyk appeared in all 17 games and started 15. He finished with 19 receptions for 200 yards and two touchdowns to go along with a rushing touchdown. He earned a ninth consecutive Pro Bowl nomination.
On March 11, 2025, Juszczyk was released by the 49ers. Head coach Kyle Shanahan rationalized the move as wanting to give Juszczyk an opportunity to see his options in free agency before they attempted to match any offer he received. Releasing him also removed some financial restrictions which his original contract burdened the 49ers with.
Following a short period as a free agent, Juszczyk re-signed with the 49ers on a two-year, $8 million deal on March 19, 2025. On December 23, 2025, Juszczyk was selected to the 2026 Pro Bowl Games, earning his 10th career Pro Bowl selection (10th consecutive) and extending his record for the most Pro Bowl selections by a fullback; he was also named a Pro Bowl starter and garnered first team All-Pro honours. In 17 games (all starts) during the 2025 season, he recorded 24 receptions for 213 yards and two touchdowns, leading NFL fullbacks in receiving yards.
