Spencer Henry Johnson is an Australian left-arm fast bowler who domestically plays for South Australia and Gujrat Titans in IPL. Johnson’s debut was in 2023 against India and South Africa, and he has played for domestic teams such as South Australia and Brisbane Heat. He wears the jersey number 45.

Johnson debuted in List A cricket during the 2017–18 JLT One-Day Cup, representing South Australia in the 15th match against Victoria. Although he didn't bat, he bowled 10 overs, securing one wicket for 72 runs in a match that South Australia won by 11 runs. Despite being released from South Australia's squad ahead of the 2020/21 season, Johnson returned for the 2020-21 Marsh One-Day Cup due to his impressive performances in South Australian Premier Cricket. Initially named in the Adelaide Strikers squad for the 2020-21 Big Bash League season, Johnson didn't feature in the tournament. However, he eventually made his BBL debut during the 2022–23 season for the Brisbane Heat on January 11, 2023. Playing in ten matches, including the final, he established himself as a dependable bowler in the death overs, contributing to the team's success in winning the 2023-2024 Big Bash League season.

In his debut first-class match, Johnson achieved figures of 6/87 against Victoria, which he surpassed in the following match against Queensland with figures of 7/47. Johnson's foray into English cricket commenced on August 10, 2023, when he debuted for the Oval Invincibles in The Hundred competition. Making a notable impression on debut, he recorded figures of 3/1 off 20 balls against the Manchester Originals.

In March 2023, Johnson earned a spot in the Australia A squad scheduled to tour New Zealand ahead of the 2023 Ashes series. During the tour's inaugural match in Lincoln, he impressed with figures of 4/53 in the first innings. Later, in August of the same year, Johnson secured a position in the 14-player squad representing Australia in the T20I series against South Africa. Making his international debut in the first match, he contributed with figures of 2/33 in a commanding 111-run victory.

Subsequently, in February 2024, he was named in Australia's squad for the T20 series against West Indies.

During the IPL Auction 2024, the Gujarat franchise secured Spencer Johnson's services for Rs 10.00 Cr. In April 2024, he concluded his IPL campaign with a match against Delhi at Narendra Modi Stadium, Ahmedabad, India, where he registered bowling figures of 22/1.

In ODIs, since 2023, he has featured in 1 match, while in T20Is, he has played 5 matches. The IPL 2024 season saw Johnson participating in 5 matches.