On March 28, 2012, the Senators signed Wideman to a two-year, entry-level contract. After graduating from Miami, he joined the Senators' American Hockey League affiliate, the Binghamton Senators for the 2012–13 season. In his first professional season, Wideman scored two goals and 18 points in 60 games. He also skated in five games for the Elmira Jackals of the ECHL. Wideman played another two full seasons with Binghamton, and had a career-year during the 2014–15 season. After recording 19 goals and 61 points in 75 games, he was awarded the Eddie Shore Award as the league's best defenseman. On June 29, 2015, the Senators re-signed Wideman to a one-year, two-way contract worth $600,000. He made his NHL debut on October 17, 2015 against the Nashville Predators. On November 7, in his fourth game, Wideman scored his first NHL goal in a 3-2 loss to the Carolina Hurricanes. During the 2017–18 season, Wideman underwent surgery to repair a hamstring injury, ending his season. Despite this, Wideman signed a one-year contract extension with the Senators on June 24, 2018.
During the 2018–19 season, on November 22, 2018, Wideman was traded by the Senators to the Edmonton Oilers in exchange for a 2020 conditional sixth-round pick. Over the course of a month with the Oilers, Wideman featured in only 5 games for 2 assists before he was dealt for a second time within the season, leaving the Oilers along with a 2019 third-round pick, to the Florida Panthers in exchange for Alex Petrovic on December 30, 2018. Wideman made his Panthers debut in a 4-3 overtime defeat to the Columbus Blue Jackets on January 5, 2019, before he was placed on waivers the following day. He cleared waivers and was assigned to AHL affiliate, the Springfield Thunderbirds, where he collected 3 goals and 13 points through 16 games from the blueline. At the trade deadline, Wideman's journeyman season continued as he was dealt for the third time, traded by the Panthers to the Pittsburgh Penguins in exchange for Jean-Sébastien Dea on February 25, 2019. He was assigned to report directly to AHL affiliate, the Wilkes-Barre/Scranton Penguins. are named Players of the Game for Team USA and Team Canada respectively at the 2016 World Championship
As a free agent from the Penguins, Wideman was signed to a one-year, two-way contract with the Anaheim Ducks on July 16, 2019. He did not feature for the Ducks during the 2019-20 season, assigned to AHL affiliate the San Diego Gulls, posting 31 points through 53 games before the remainder of the season was cancelled due to COVID-19.
Abroad
As an impending free agent from the Ducks, Wideman opted to pursue a career abroad in agreeing to a one-year contract with Russian club, Torpedo Nizhny Novgorod of the KHL, on June 1, 2020.
