Tillo attended Sioux City North High School in Sioux City, Iowa, where he played football, basketball, and baseball. As a junior in 2014, he pitched to a 6-0 record and a 0.98 ERA. Following his senior basketball season in 2015, he was named Iowa Mr. Basketball after averaging 24.5 point, 9.0 rebounds, and 4.4 assists per game. During his senior baseball season, he went 5-1 with a 3.08 ERA while batting.369. Due to being uncertain on whether he wanted to pursue basketball or baseball at the collegiate level, he did not commit to a college for either sport until June of his senior year, when he ultimately decided to play college baseball at the University of Kentucky. After his senior year, he was drafted by the Minnesota Twins in the 39th round of the 2015 Major League Baseball draft. Tillo chose to honor his commitment to Kentucky, and not sign with the Twins. In 2016, his freshman year, he pitched only innings. Following the year, he transferred to Iowa Western Community College in order to be closer to home and to transition back into a starting pitcher. In 2018, his sophomore year and first year at Iowa Western, he went 5-1 with a 2.86 ERA, striking out 57 over 44 innings and nine games. After the season, he was drafted by the Kansas City Royals in the third round of the 2017 Major League Baseball draft.
Professional career
Tillo signed with the Royals and made his professional debut with the Arizona League Royals before being promoted to the Burlington Royals. Over ten games between the two clubs, he pitched to a 3-2 record with a 4.42 ERA over innings. In 2018, he began the season with the Lexington Legends before being promoted to the Wilmington Blue Rocks. Starting 26 total games between the two teams, Tillo went 4-6 with a 4.76 ERA, striking out 100 over innings and compiling a 1.50 WHIP. Tillo began the 2019 season back with Wilmington, and was promoted to the Northwest Arkansas Naturals in July, finishing the season there. Over 29 games for the season, he compiled an 8-9 record with a 3.72 ERA, striking out 85 over innings. Following the season, he pitched in the Arizona Fall League for the Surprise Saguaros. And also, on October 10, he was selected for the United States national baseball team in the 2019 WBSC Premier 12. In the tournament, he went 0-0 with a 2.08 ERA in three relief appearances covering innings in which he struck out eight batters.
