He experienced a growth spurt in his junior year and left Elk River as a senior to begin playing for the Sioux Falls Stampede of the United States Hockey League (USHL).

He subsequently earned a full ride to play for the Colorado College Tigers for four years before signing an entry-level contract with the Minnesota Wild.

Prosser was born on May 7, 1986, in Elk River, Minnesota,[1] to mother Margaret, an aerobics instructor and personal trainer, and father Chris,[2] who used to play hockey at Anoka High School and at West Point.

[9] During the off-season, he travelled with members of the team on the Minnesota Wild Road Tour as part of a fundraiser for Sioux Falls Youth Hockey.

[11] Prosser returned to the Wild for 2010–11 training camp but was re-assigned to their American Hockey League (AHL) affiliate, the Houston Aeros, to begin the season.

[15] After being re-called to the NHL level in early January, Prosser suffered an illegal check from Phoenix Coyotes forward Raffi Torres who was subsequently suspended two games for charging.

As a result, he then scored his first career NHL goal on February 7, 2012, against Curtis Sanford of the Columbus Blue Jackets in an eventual 3–1 loss.

[20] On July 21, 2014, after four seasons within the Wild organization, Prosser left as a free agent to sign a one-year, two-way contract with the St. Louis Blues.

[22] Nearing the conclusion of the 2015–16 season, Prosser was the Wild's nomination for the Bill Masterton Memorial Trophy as a "player who best exemplifies the qualities of perseverance, sportsmanship and dedication to hockey."

His nomination was the result of his support for charity initiatives including Defending The Blue Line, Children’s Hospitals and Clinics of Minnesota and Wishes & More.

[26] On July 1, 2019, Prosser again left the Wild as a free agent to sign a two-year, two-way contract with the Philadelphia Flyers worth $700,000 per season.

"[30] As a result of injuries, Prosser made his debut with the Philadelphia Flyers on January 28, 2021, against the New Jersey Devils, where he netted his first goal since April 2018.