Mychal Mulder was adopted by parents Randy Mulder and Jennifer Gignac at three months old. His father worked at General Motors before being forced to retire after a leg injury. His father named him after Mychal Thompson. Mychal Mulder was raised in Windsor, Ontario, alongside an elder adopted sister, Cynthia. He played basketball at Catholic Central High School, where he was coached by Pete Cusumano. Mulder was considered a Top 10 Canadian prospect in 2013.
College career
Mulder received a single NCAA Division I scholarship offer, to play for the Detroit Mercy Titans men's basketball team. Mulder opted to begin his college basketball career at Vincennes University. As a sophomore, he averaged 15.7 points and 6.4 rebounds per game, shooting 46.3 percent from behind the arc. He led the team to a 33–2 record, was named a JUCO All-American and was rated the 13th-best junior-college prospect by 247Sports. He then transferred to play for the Kentucky Wildcats men's basketball team. He chose Kentucky over several other colleges, including Creighton, Indiana, and Wichita State. As a senior at Kentucky, Mulder made two starts and averaged 4.7 points and 1.5 rebounds in 10.6 minutes per game, shooting 40.3% from the field and a team-high 92.3% from the free throw line.
Mulder went undrafted in the 2017 NBA Draft, later Mulder was selected ninth overall in the 2017 NBA G League draft by the Windy City Bulls. In his second season with the Bulls, Mulder posted 13.7 points, 4.1 rebounds, 1.6 assists in 32.9 minutes per game. In May 2019, Mulder was invited to the NBA G League Elite Camp.
On February 27, 2020, the Golden State Warriors announced that they had signed Mulder to a 10-day contract. He made his debut against the Los Angeles Lakers that same day. Mulder had two points and four rebounds in that game, which was a 116–86 loss. On March 1, 2020, Mulder had a career-high 17 points, along with two rebounds, one assist, one block and one steal in just his third game with the Warriors, a 124–110 loss against the Washington Wizards. On March 7, 2020, Mulder started against the Philadelphia 76ers - setting a new career-high 18 points and 3 assists during his last game of his first 10-day contract, a 118-114 win. Following that game, Mychal confirmed that he was in fact named after teammate Klay Thompson's dad, Mychal Thompson. On March 10, 2020, after his 10-day contract expired the Warriors signed him to a multi-year contract.
