However, following the 2013–14 season, Lomberg left the school after being suspended from the Black Bears due to an assault and disorderly conduct charge, the latter of which he pleaded guilty to.

Lomberg scored 24 goals and 43 points in the regular season while playing with future Winnipeg Jets forward Kyle Connor and serving as team captain[3] to help lead the Phantoms to the Anderson Cup.

Lomberg's play with the Phantoms caught the eye of the Calgary Flames' amateur scouting staff, earning him an invite to their annual fall development camp.

Impressed with his work ethic and determination, the Calgary Flames rewarded Lomberg with a two-year entry-level contract worth $710,000 per season in the NHL on March 17, 2017.

[8] After helping the Panthers claim their first Stanley Cup in franchise history, Lomberg left as a free agent and was signed to a two-year, $4 million contract in a return with his original club, the Calgary Flames, on July 1, 2024.