For others (Late but worthy), I installed Jenkins via Brew, so I add Docker's path to the file below: /usr/local/Cellar/jenkins-lts/2.176.3/homebrew.mxcl.jenkins-lts.plist (Whole file looks like below)
Label homebrew.mxcl.jenkins-lts ProgramArguments /usr/libexec/java_home -v 1.8 --exec java -Dmail.smtp.starttls.enable=true -jar /usr/local/opt/jenkins-lts/libexec/jenkins.war --httpListenAddress=127.0.0.1 --httpPort=8080 RunAtLoad EnvironmentVariables PATH /usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/Applications/Docker.app/Contents/Resources/bin/:/Users/Kh0a/Library/Group Containers/group.com.docker/Applications/Docker.app/Contents/Resources/bin



