Luke Farrell

Farrell attended Saint Ignatius High School in Cleveland, Ohio, and Northwestern University, where he played college baseball for the Northwestern Wildcats. In 2010, his freshman year, he was diagnosed with a schwannoma, a benign nerve sheath tumor on his jaw, that required surgical removal. He developed another tumor that was removed and treated with radiation therapy in 2011. In his four years at Northwestern, Farrell had 208 strikeouts, and was awarded with the Big Ten Medal of Honor his senior season.

Kansas City Royals

The Kansas City Royals selected Farrell in the sixth round of the 2013 MLB draft. Farrell made 10 starts with Rookie Advanced level Idaho Falls, where he went 1–3 with a 6.65 ERA, although he did strike out 45 batters in 43 ¹⁄₃ innings. Farrell's struggles continued in 2014 with Single-A Lexington, going 2–12 in 19 starts with a 5.25 ERA while striking out 8.5 batters per 9 innings. Farrell opened the 2015 season with High-A Wilmington, then was promoted to Double-A Northwest Arkansas in May. Farrell made 16 starts at Double-A, going 5–3 with a 3.09 ERA, although his K/9 dropped to 6.3. Farrell pitched 2016 with Triple-A Omaha, where in 19 appearances (14 starts), he went 6–3 with a 3.76 ERA. He returned to Omaha to begin the 2017 season, where he made 13 starts before earning a promotion to the major leagues on July 1.

When the Royals needed a starting pitcher for the first game of a doubleheader against the Minnesota Twins, Farrell was called up from Omaha to make his major league debut. He gave up 5 runs in 2 ²⁄₃ innings and left the game as the pitcher of record, but did not receive a loss as Kansas City came back to win the game. Originally recalled as the 26th player for the doubleheader, Farrell was optioned back to Omaha the next day. Following the Royals' acquisition of three major league pitchers from the San Diego Padres, Farrell was designated for assignment on July 24.

Los Angeles Dodgers system

Farrell was traded to the Los Angeles Dodgers in exchange for cash considerations on July 28, 2017, and was assigned to the Triple-A Oklahoma City Dodgers. Farrell made one appearance for Oklahoma City, giving up 2 earned runs in 4 ²⁄₃ innings.

Cincinnati Reds

On August 9, 2017, Farrell was claimed off waivers by the Cincinnati Reds, and assigned to the Triple-A Louisville Bats. He was called up by the Reds on August 23, when he made his National League debut and pitched 3 innings of scoreless relief.

Luke Farrell is the youngest of three sons born to Boston Red Sox manager John Farrell. John Farrell took a one-day leave from the Red Sox to be at Kaufmann Stadium on July 1, 2017, to watch Luke Farrell make his MLB debut; the Red Sox were managed that day by bench coach Gary DiSarcina. On September 23, 2017, Luke Farrell pitched a scoreless inning of relief against the Red Sox, which was the first time in MLB history that a son pitched against a team managed by his father. Luke Farrell's brothers, Jeremy and Shane, were both selected in the MLB Draft, with Jeremy playing in the minor leagues from 2008 through 2015.