Jack Killilay put in six seasons of minor-league ball before joining the 1911 Boston Red Sox and he put in five seasons after departing the Red Sox. His one year in the majors was a 4-2 season in 1911 (61 innings, with a 3.54 earned-run average) from his debut on May 13 to his last game, on September 22. At the plate, he was 1-for-24, but it was a double. His .042 batting average was supplemented by two walks for a .115 on-base percentage. He drove in one run. In the minors, Killilay won 145 games. He was a right-handed pitcher with a playing weight of 165 pounds, and was one inch less than 6 feet tall.
Killilay was also in the middle among his brothers and sisters, with Edward, Martin, and Harry older and Lillian, Mabel, and James younger. Their parents were Martin Killilay, a bricklayer, and Susan Killilay, a saloon keeper in Leavenworth, Kansas, where John William Killilay was born on May 24, 1887. Both parents were born in the United States (Pennsylvania and Missouri, respectively); Martin’s parents came from Ireland. By the time Jack was playing baseball for a living, Martin had moved to farming and operated his own dairy in Leavenworth. Jack attended ten years of school.
Three of Jack’s brothers also played pro ball. Martin (who played from 1903 to 1916), Harry (1906-1913), and Ed (who played in 1910). Writing in the Los Angeles Times, Harry A. Williams said that it was Martin who gave Jack a helping hand. Jack had left high school to transfer to business college, but had his eye on baseball. In 1907 Martin was “then playing under Russ Hall with Butte” and put in a word for Jack.
For someone who didn’t hit much (his career minor-league average was only .157), it’s notable that Killilay’s first year in Organized Baseball was as an outfielder in the Texas League. He played for the Austin Senators and then the Dallas Giants in 1905. (Austin was dropped by the league in early June.) He hit .200 in 30 at-bats, with one double. From 1906 on, beginning in the Kansas State League, Killilay pitched. That year he worked for the Iola Grays, who moved to Cherryvale in mid-June and became the Cherryvale Boosters. He had success, winning 13 and losing six.
Killilay’s next three seasons were in the Class B Northwestern League. He started with the Butte Miners in the first part of 1907, apparently thanks to brother Martin. He did well and was traded to the Spokane Indians for pitcher Lee Samuels and third baseman William Adams. He pitched for Spokane through the 1910 campaign. He won 13 games again in his first year, then became a 20-game winner in 1908 (20-15). In 1909 he was 19-15 and in 1910 he was 24-10 and attracted the attention of the Red Sox, who drafted him on September 1. Fellow pitcher Jesse Baker was 28-10 for Spokane, and was signed by the Chicago White Sox for 1911. The Indians easily placed first in the four-team league.
Boston Globe sportswriter Tim Murnane noted Killilay’s signing in a January preview of the 1911 season, saying that he had “wound up the  season in a phenomenal manner. His hitting was, like most pitchers, very low, being for .120. He is a large, rangy fellow and has been touted as one of the best youngsters turned out last season.” 
Boston invited Killilay to 1911 spring training in Redondo Beach, California. It was an unusual year that saw the Red Sox break into two teams and play separately up and down in the state of California and then through two different routes as they headed back east. In a further indication of Killilay’s difficulties as a batter, consider the April 6 game at St. Joseph, Missouri, where the local host team, the St. Joseph Drummers, beat Boston, 5-4. At one point, “Killilay failed to bunt the ball for a squeeze and Williams was a dead duck at home plate. Killilay had a rough day. He struck out four times in a row without even getting the bat on the ball for a foul – 12 strikes without any bat contact whatsoever.” 
Killilay stuck with the big-league team for the full 1911 season, though the Washington Post wasn’t unfair in calling him “an experiment.”  His major-league debut – the first part of the experiment – came on May 13. It was in Detroit, and a dramatic game that saw the Tigers leading the Red Sox 10-4 after eight innings. But the Red Sox scored seven times in the top of the ninth to take an 11-10 lead. Detroit tied in the bottom of the ninth, and Boston scored twice more in the top of the tenth, eventually winning the game. Killilay was the third of four Red Sox pitchers, coming in with the score 10-3 (Ty Cobb’s third-inning grand slam off starter Ed Karger was said at the time to be the longest hit of his career), and throwing three scoreless innings (sixth, seventh, and eighth). He walked two and gave up two hits, but was unscored upon – and in a position to get the win had not the Tigers tied it back up in the ninth off reliever Smoky Joe Wood. Joe Riggert had pinch-hit (and tripled) for Killilay in the seven-run top of the ninth.
Killilay started the game on May 18 –first of his seven starts – and lasted 4 1/3 innings. It was the game in which he doubled, but the White Sox batters were too much for him (nine hits) and he struggled with control (three walks). The game was a win for the White Sox, 12-8. Killilay didn’t get another start for a month.
On June 21 he started against New York, in New York. It was a close game through six innings, a 3-1 Boston lead, and then the Red Sox scored five times in the top of the seventh. Killilay pitched well, holding the Highlanders to just five hits in seven innings, but he started the eighth with a walk, a single, and a hit batsman. He got one out and was relieved, but was responsible for two runs. It was his first major-league victory.
After the Red Sox dropped the first game of a doubleheader to New York on June 29, Killilay pitched the second game. He struck out three times at the plate, but he won, 3-2, allowing one run in the first and one in the eighth in a complete-game win. “Killilay has something on the New York boys,” murmured the Globe.
Killilay worked as a spot starter, without a start between July 4 and August 12, though he contributed in relief, notably allowing just one hit in the final four innings on July 15 against Detroit. KILLILAY BLOWS UP IN THE SIXTH, headlined the August 12 Globe. He had done well against the Athletics in Philadelphia until a four-run sixth that sealed his fate. It was his first loss of the year. A 4-1 loss to the Athletics on September 8 was his last start, and the only other loss Killilay bore. He finished the season with a 4-2 record and a 3.54 ERA in 61 innings of work. 
After the season Red Sox owner John I. Taylor made a move that suited his business interests. He had purchased the Jersey City Skeeters team and moved several of his players to fill out the Skeeters roster. Killilay had played semipro ball during the winter, pitching for the Los Angeles Brewery team. When he was asked to go to Bermuda for Jersey City’s spring training, “Killilay balked.”  He refused to go. Taylor dealt with the issue by selling Killilay to the Oakland Oaks of the Pacific Coast League, where he worked from 1912 through 1914. His 15-4 record in his first season gave him the highest winning percentage (.789) in the league that season. Oakland won the pennant – but a part of Killilay no doubt wished he’d been with the world champion Boston Red Sox.
The Oaks plunged from first to last in 1913, and Killilay’s 12-23 reflected the plunge. He was 12-18 in 1914. All three seasons he posted an earned-run average under 3.00. Oakland changed managers in midseason of 1914 and it was said at the time that “Handsome Jack” was “practically certain to go.” Killilay couldn’t come to terms with the Oaks for 1915, and the team tried to sell his contract but no one was willing to pay the purchase price. The Oaks cut him loose, giving him his release and Killilay was snapped up right away by the San Francisco Seals. “With a club making a few runs behind me, I will win, but there was not a chance with Oakland last season,” he said. “I knew I would catch on all right, but they didn’t treat me fairly to hold up my release until so late.” By August, he’d been moved to the Salt Lake City Bees. His PCL record that season was a combined 8-10.
In 1916 Killilay was back in Montana, pitching again in the Northwestern League for one last season, with the Great Falls Electrics. In 1918 and 1919, during and immediately after the World War, he served in the Medical Department of the armed forces.
Killilay spent his latter years in Tulsa, Oklahoma, and was living in the Hotel Albany at the time he completed his player questionnaire for the Baseball Hall of Fame. He died in Tulsa of a coronary thrombosis on October 21, 1968, at the age of 81.
In addition to the sources noted in this biography, the author also accessed Killilay’s player file from the National Baseball Hall of Fame, the online SABR Encyclopedia, the Encyclopedia of Minor League Baseball, Retrosheet.org, and Baseball-Reference.com.
 Los Angeles Times, January 26, 1913
 Boston Globe, January 31, 1911. Murnane had clearly never seen Killilay, since he was neither large nor rangy.
 Bill Nowlin, The Great Red Sox Spring Training Tour of 1911 (Jefferson, North Carolina: McFarland & Co., 2011)
 Washington Post, May 10, 1911
 For what it’s worth, Jesse Baker, Killilay’s Spokane teammate who went up to the majors the same year as Killilay, played in the majors only in 1911, and was 2-7 with the White Sox.
 Los Angeles Times, January 14, 1912
 Los Angeles Times, January 26, 1913
 Los Angeles Times, June 8, 1914
 Los Angeles Times, March 29, 1915