|Date of birth||October 8, 1998|
|Place of birth||Vancouver, British Columbia, Canada|
|Height||1.80 m (5 ft 11 in)|
|Aurora Youth SC|
|Richmond Hill SC|
|2016–2017||St. John's Red Storm||36||(10)|
*Club domestic league appearances and goals, correct as of June 24, 2022|
‡ National team caps and goals, correct as of June 13, 2022
Johnston was born in Vancouver to a Canadian father and Northern Irish mother from Newtownards. His family moved to Montreal when he was four, where he began playing soccer with Lakeshore SC. The family again moved to Aurora, Ontario when he was seven. There, he played youth soccer with Aurora FC and Richmond Hill SC. He made his debut in the Canadian youth program at an under-18 camp in 2015, when he was 16. He played youth soccer with ANB Futbol, and earned a tryout with French club Troyes AC while there. In 2015, he joined Vaughan SC, helping them win the 2015 U-18/U-19 Disney Soccer Showcase, the 2015 OYSL U-18 League title, and the 2016 and 2017 U21 Ontario Cup.
Johnston attended St. John's University for two years, before moving to Wake Forest University in 2018 in search of a bigger challenge both in soccer and academically. He switched positions from central midfield to right-back upon joining Wake Forest.
While in college, Johnston also played with League1 Ontario side Vaughan Azzurri from 2015 to 2019. Johnston played in the 2019 Canadian Championship for Vaughan Azzurri and was sent off in the second leg of the away goals defeat to the HFX Wanderers.
On January 9, 2020, Johnston was selected 11th overall by Nashville SC in the 2020 MLS SuperDraft. He officially signed with the club on February 25, 2020. Due to the COVID-19 pandemic, which included Nashville withdrawing from the MLS is Back Tournament due to an outbreak amongst the team, his debut was delayed until August 12 against FC Dallas, coming on as a substitute. He made his first start four days later, also against Dallas. He helped the club reach the MLS Playoffs in their debut season, making 18 appearances.
On September 22, 2021, Johnston scored his first MLS goal in a 1–5 victory over Inter Miami. In December 2021, Nashville announced they were exercising Johnston's contract option, keeping him at the club through the 2022 MLS season.
On December 23, 2021, CF Montréal acquired Johnston from Nashville in exchange for a million dollars in allocation money, with Nashville also retaining a percentage of a transfer fee in a future sale. Montreal confirmed the deal on December 27 and announced Johnston had also signed a new contract taking him through 2023, with options for 2024 and 2025. He made his debut for Montreal on February 23, as a substitute against Liga MX side Santos Laguna in the club's second leg of their 2022 CONCACAF Champions League tie. Johnston scored his first goal for Montreal on May 14, scoring the second goal in a 2-0 victory against Charlotte FC.
Johnston accepted an invitation to the Canadian senior national team camp in January 2021. He made his debut for Canada on March 25, 2021, as a 69th-minute substitute against Bermuda, in the first round of 2022 World Cup qualifying, and scored his first goal for Canada in the following match against the Cayman Islands. In June 2021 Johnston was named to the 60-man preliminary squad for the 2021 CONCACAF Gold Cup, and on July 1 he was named to the final squad.
- As of match played June 24, 2022
|Vaughan Azzurri||2015||League1 Ontario||2||0||—||—||—||2||0|
- As of match played June 13, 2022
- As of March 29, 2021
- Scores and results list Canada's goal tally first, score column indicates score after each Johnston goal.
|1||March 29, 2021||IMG Academy, Bradenton, United States||Cayman Islands||6–0||11–0||2022 FIFA World Cup qualification|
- Alistair Johnston at the Canadian Soccer Association (also available in French)
- Cudmore, John (October 27, 2021). "Aurora's Alistair Johnston has Canada's back on FIFA World Cup qualifying trail". Aurora Banner.
- Davidson, Neil (November 19, 2020). "Canadian fullback Alistair Johnston turning heads with expansion Nashville SC". Toronto Star.
- "Player Success". ANB Futbol. June 30, 2014.
- "Seven ANB players travel to Europe". Soccer Academy Alliance Canada. April 22, 2016.
- "Alistair Johnson profile". St. John's Red Storm.
- "Vaughan SC Win Fourth U-21 Men's Ontario Cup in a Row". Ontario Soccer Association. July 23, 2017.
- Davidson, Neil (January 9, 2020). "Canadian Alistair Johnston looks to take next soccer step in MLS SuperDraft". CTV News.
- Davidson, Neil (January 9, 2020). "Crop of Canadians taken early in MLS draft". CBC.
- "Nashville SC Extends Offers to 2020 MLS SuperDraft Selections | Nashville SC". February 25, 2020.
- Lavigne, Keegan (June 3, 2020). "Aurora soccer player Johnston focuses on positive mental state during pandemic". The Toronto Observer.
- Le Miere, Jason (August 17, 2020). "Nashville SC youngster Alistair Johnston hailed by coach Gary Smith after impressive first MLS start". Major League Soccer.
- Everett, Tatum (November 16, 2020). "One-on-one with Nashville SC's Alistair Johnston on 2020 season and a look at playoffs". WZTV NAshville - Fox 17.
- "Recap: Inter Miami CF 1, Nashville SC 5". Major League Soccer. Retrieved September 22, 2021.
- "Nashville Soccer Club Announces 2021 Roster Decisions". Nashville SC. December 10, 2021.
- "CF Montreal acquires CanMNT's Johnston". TSN. December 23, 2021.
- "CF Montréal acquires Canadian international Alistair Johnston". CF Montréal. December 27, 2021.
- "CF Montréal 3-0 Santos Laguna". CF Montréal. February 23, 2022.
- "Charlotte FC 0-2 CF Montréal". CF Montréal. May 14, 2022.
- Davidson, Neil (December 23, 2020). "TFC's Ayo Akinola accepts invite to Canadian national team camp". CBC.
- "Larin, Davies team up to help Canada crush Bermuda in World Cup qualifier". Retrieved March 25, 2021.
- Jacques, John (March 29, 2021). "Canada Coasts Past Cayman Islands In Historic Eleven-Goal Win".
- "Davies, David highlight Canada's preliminary roster for Gold Cup". June 18, 2021.
- "Canada Soccer Announces 2021 Gold Cup Roster". Canadian Soccer Association. July 1, 2021.
- Alistair Johnston at Soccerway
- "Vaughan Azzurri - 2016 Regular Season - Roster - # - Alistair Johnston -". league1ontario.com.
- "Vaughan Azzurri - 2017 Regular Season - Roster - # - Alistair Johnston -". league1ontario.com.
- "Vaughan Azzurri - 2018 Regular Season - Roster - # - Alistair Johnston -". www.league1ontario.com.
- "Vaughan Azzurri - 2019 Playoffs - Roster - # - Alistair Johnston -". league1ontario.com.