Fredette was the 2011 National Player of the Year in college basketball after ranking as the leading scorer in all of NCAA Division I during his senior season for the BYU Cougars.

As Fredette developed, his father took him on occasional road trips to Hartford and New York City for more intense competition, and also helped to coach his AAU teams.

Her brother Lee Taft, a personal trainer who now operates a speed training school in Indianapolis, started him on running drills as a five-year-old, and still works with Fredette.

[9] Until February 24, 2015, Fredette held the all-time Section 2 high school record, when he was surpassed by Lake George senior Joel Wincowski.

[10] Fredette was named first-team all-state by the New York State Sportswriters Association and the Times Union as a junior and senior.

He had several memorable on-court moments in his career at Glens Falls, including 12 different 40-point performances in his senior season,[citation needed] and a shot against Voorheesville High School's Andrew Catellier in the season opener of his junior year in which he banked a three-pointer off the glass and in with his opposite hand to force overtime at the end of regulation.

He played AAU for the Albany City Rocks alongside future Penn State University point guard Talor Battle and Mark Domaracki.

[11] Fredette averaged 25 points per game to help the Rocks to a third-place win over the Minnesota Magic at the 2006 AAU National Championships.

[15] On March 11, 2010, Fredette scored 45 points, shooting 10-for-23 from the field, and making 23-of-24 free throws, in his team's 95–85 win over TCU.

He scored 37 points and hit two three-pointers in double-overtime to seal the Cougars' 99–92 win over 10th-seeded Florida, the first time they had reached the second round of the tournament in 17 years.

On January 26, 2011, in the Mountain West Conference's first battle of top-10 teams, which attracted a crowd of over 22,700 at BYU's Marriott Center, Fredette scored 43 points against previously undefeated San Diego State, ending the game in a 71–58 victory.

He became the Mountain West Conference's all-time leading scorer on February 5, 2011, with a 29-point performance versus UNLV in the Marriott Center.

[22] On March 11, 2011, Fredette broke BYU's career scoring record, previously held by Danny Ainge, in the semifinals of the Mountain West Conference Championship Tournament.

He set the school's single-game scoring record with a career-high 52-point game against New Mexico, to whom BYU had lost twice in the regular season.

[23] Fredette and number 12-ranked BYU were unable to hold off an aggressive 5th-ranked San Diego State team in the Mountain West Conference championship game, and lost, 72–54.

[24] On March 19, 2011, Fredette again led BYU's scoring with 34 points as they defeated 11th-seeded Gonzaga, 89–67, and advanced to the third round of the NCAA Tournament (Sweet Sixteen) for the first time since 1981, falling to the Florida Gators (in overtime) in a rematch of the game from the previous year.

[33] After BYU's nationally televised game against San Diego State in which Fredette scored 43 points, the media attention around him became significant.

He was subsequently traded to the Sacramento Kings in a deal with Milwaukee and the Charlotte Bobcats involving John Salmons, Beno Udrih, Shaun Livingston, Corey Maggette, and Stephen Jackson.

[40] Fredette made his rookie debut in a preseason game against the Golden State Warriors on December 17, 2011, scoring 21 points (tied for team high) and recording 4 rebounds.

[71][72] On November 11, Fredette recorded a career-high 75 points (including him scoring a record-high 40 in the fourth quarter) in a 137–136 loss to the Beikong Fly Dragons.

On July 15, 2019, Fredette signed a two-year contract with Panathinaikos of Greece's top-tier level Greek Basket League and the EuroLeague.

On August 5, 2021, as it became clear that foreign players likely would not be able to compete in the 2021–22 CBA season, Fredette was signed to the Denver Nuggets Summer League roster for the second time.

[86] In 2022, Fredette made his 3x3 debut at the 2022 Red Bull USA Basketball 3X East Regional, which took place October 8–9 in New York, and helped team NYC Blue win the event.

On October 25, 2022, Fredette, Canyon Barry, Kareem Maddox, and Dylan Travis were named to the USA Men's 2022 3x3 AmeriCup team.

He finishes in traffic with a dozen deft moves, including a scoop shot, originating from his waist, that he can make with either hand.

Kevin Durant of the Oklahoma City Thunder posted on his Twitter account that "Jimmer Fredette is the best scorer in the world!

TJ, a rapper whose song "Amazing" was written for his brother, said, "I see him play, and it gives me chills sometimes when he hits some of those big shots and the crowd is going crazy.

"[98] In an article published in Sports Illustrated, Marcus Morris, a forward at Kansas, noted the work ethic and moral character Fredette exhibited while at USA Basketball camp.

"[36] An unusual set of Fredette fans resided in the Mount McGregor Correctional Facility, a medium-security prison, where he and his older brother played games with the inmates.

[102] After signing with the CBA's Shanghai Sharks, Fredette has become a dominant player in the Chinese Basketball League, leading his team to the playoffs in 3 of his 4 years there.