In her freshman season with the Wisconsin Badgers women's ice hockey program, Decker scored the Badgers' first goal of the season in a game against North Dakota. During the season, she accumulated seven multi-point games and four multi-goal games. She was third in team scoring despite missing almost half of the first part of the season. On September 25, 2011, Decker scored her third career hat trick in a 13–0 defeat of the Lindenwood Lady Lions ice hockey program. Her 12-game winning goals during the 2010–11 season are a program record. She holds the Badgers longest scoring streak at 32 games. During the streak she accumulated 77 points. In her junior season, Decker won the 2012 Patty Kazmaier Award.
USA Hockey
She won gold at the 2009 IIHF World Women's U18 Championship. On January 28, 2011, it was announced that Decker was named to the preliminary roster for the US Women's National Team. From April 4 to 12, 2011, she was one of 30 players that took part in a selection / training camp and was named to the final roster that participated at the 2011 IIHF Women's World Championship. At the 2011 IIHF Women's World Championship, Brianna Decker was among the tournament's top five scorers. Decker's 11 points placed her second. In 2017, Decker was a member of the winning US team for the 2017 IIHF Women's World Championship, receiving two assists in the final against Canada.
Professional
CWHL
Making her debut for the Boston Blades on January 17, 2015, Decker accumulated seven points in an 11–3 win against the Brampton Thunder. Decker would finish the season leading all American-born players in scoring, while ranking second overall in the scoring race for the Angela James Bowl with 32 points. In addition, she tied with Blades teammate Tara Watchorn as the league leaders in plus/minus rating with a +25. During the 2015 Clarkson Cup playoffs, Decker led all players in scoring, while registering two goals in the championship game, a 3–2 overtime win over the Montreal Stars.
NWHL
Signing as a free agent with the Boston Pride of the National Women's Hockey League, Decker made league history on October 25, 2015. During a 5–3 road win against the Buffalo Beauts, Decker would score the first hat trick in league history. All three goals were scored against Beauts goaltender Brianne McLaughlin. Decker was awarded Most Valuable Player consecutively by the NWHL for her performance in the 2015–16 season and 2016–17 season.
Return to CWHL
On July 24, 2018, Decker and fellow Team USA gold medalist Kacey Bellamy signed as free agents with the Calgary Inferno. Decker would score the game-winning goal versus Les Canadiennes de Montreal in the 2019 Clarkson Cup finals, with Bellamy gaining the assist. Of note, Decker would also be recognized as the MVP of the 2019 Clarkson Cup playoffs.
NHL
On January 25, 2019, Decker participated in the NHL All-Star Skills Competition, in which she demonstrated the premier passing drill event. Her demo time of 1:06 was faster than all eight men who competed in the event. The $25,000 prize money went to Leon Draisaitl, who finished at 1:09. Ice hockey equipment manufacturer CCM announced that it would pay Decker $25,000 for achieving the fastest time.
PWHPA
Decker participated in the #ForTheGame movement in connection with the PWHPA, beginning May 2019. She played for Team Johnston in PWHPA's Dream Gap exhibition tour.
Career statistics
NCAA
WCHA
CWHL
Season
GP
G
A
Pts
PIM
+/-
PPG
SHG
GWG
2014–15
12
16
16
32
10
+25
1
0
2
NWHL
Awards and honors
NCAA
Patty Kazmaier Memorial Award winner
RBK Hockey/AHCA Division I second-team All-American