Giljegiljaw began his professional career with the Cleveland Indians as a non-signed free agent, being signed on November 29, 2012 by Jason Lynn and Allen Lin.

[3] From 2014 to 2016, Giljegiljaw spent time with the rookie-level Arizona League Indians, Low-A Mahoning Valley Scrappers, and Single-A Lake County Captains, failing to get more than 150 plate appearances in a season.

The 2017 season with the Single-A Lake County saw Giljegiljaw break this streak by getting 518 plate appearances and getting selected as a Midwest League Postseason All-Star.

[4] Giljegiljaw spent time with the High-A Lynchburg Hillcats, Double-A Akron RubberDucks, and Triple-A Columbus Clippers in 2018, slashing .272/.340/.425 with 10 home runs and 51 RBI.

[1] He has used his Paiwan name, meaning "brave warrior" and given to his by his grandmother, with his family and adopted it legally in 2019 so that it would be written on his jersey while playing for Cleveland.