Sean Doolittle is a former Major League Baseball pitcher who played for the Oakland Athletics, Washington Nationals, and Cincinnati Reds. He was born on September 26, 1986, in Rapid City, South Dakota, and attended the University of Virginia, where he played college baseball.

Doolittle was drafted by the Oakland Athletics in the first round of the 2007 MLB draft and made his debut in 2012. He quickly established himself as a reliable relief pitcher, earning his first save in May of that year. Over the next few seasons, Doolittle became one of the Athletics' most dependable bullpen arms, posting a 2.99 ERA and 44 saves in 2014 and earning his first All-Star selection in 2014.

Injuries limited Doolittle's effectiveness in 2015 and 2016, but he bounced back in 2017, recording 24 saves and a 2.45 ERA. However, the Athletics traded him to the Washington Nationals in July of that year, where he became the team's closer and helped lead them to a World Series championship in 2019.

Doolittle's time with the Nationals was marked by both success and injury. He recorded 29 saves in 2018 and was named an All-Star for the second time in his career, but he struggled with injuries in 2019 and 2020, posting a 5.87 ERA in 2020. The Nationals declined his option for the 2021 season, and he signed with the Cincinnati Reds, where he pitched in a limited role before being released in August.

Throughout his career, Doolittle was known for his fastball and slider, as well as his ability to induce ground balls. He finished his career with a 3.07 ERA, 400 strikeouts, and 63 saves in 441 innings pitched. Off the field, Doolittle was also known for his advocacy for social justice and his work with military veterans and their families.

In July 2021, Doolittle announced his retirement from baseball, citing a desire to spend more time with his family and pursue other interests. He leaves behind a legacy as one of the game's most reliable and respected relief pitchers, as well as a leader in the fight for social justice and equality.