Widell originally played the trombone in his high school band. In football he didn't start until his junior year. He also was the center for the basketball team.
He accepted a scholarship to play at Boston College and was a backup at left tackle as a freshman. The next year, he was part of the rotation at center.
Widell was a three-year starter and played multiple positions along the offensive line, before settling in at right tackle. He also was the team's long snapper on special teams.
In 2003, he was inducted into the Boston College Varsity Club Athletic Hall of Fame.
Widell was selected in the fourth round (94th overall) of the 1988 NFL Draft by the Dallas Cowboys. He started 8 games at left tackle and became the first rookie in franchise history to start a season opener at offensive tackle. In his second year he started in 2 games.
On August 24, 1990, he was traded to the Denver Broncos in exchange for a seventh round selection in 1991 (#173-Leon Lett) and an eighth round selection in 1992 (#222-Mike Pawlawski).
With the Denver Broncos, he joined his brother Doug Widell (who was also his teammate at Boston College), becoming the first brothers in the NFL's modern era to play together on the same offensive line. In 1990, he appeared in all 16 games serving as the long snapper and started at left guard in the final 5 contests.
In 1991, he started two games at left guard and replaced Keith Kartz as the starting center for the playoff games against the Houston Oilers and the Buffalo Bills.
In 1992, he started the season opener at center. The next year, he started 15 games, playing between guard and center. In 1994, he started 16 games at left guard.
Widell only missed one game with the Broncos, while playing at guard, tackle, center and long snapper.
On March 15, 1995, he signed as a free agent with the Jacksonville Jaguars and was named the franchise's first starting center. He was the regular starter at center for 3 seasons.
Widell signed as a free agent with the Atlanta Falcons in 1998. He was a part of the Atlanta Falcons' Super Bowl XXXIII losing team. He was released on February 17, 1999, after being inactive in 14 games and having played in only one.