[1][2] After completing his education, he moved to Sydney where he married Elizabeth Ann Jane Mullarky in 1871.

[citation needed] The couple had the following children:[5] About 1882 they moved to Brisbane and then many years later back to Sydney.

[1] John Allworth Clark was an alderman representing the North Ward of the Brisbane Municipal Council from 1889 to 1898.

[14] Whilst mayor, Clark served as a line umpire in an 1891 intercolonial rugby union match between Queensland and New South Wales.

[20][21] In 1894 Clark proposed that women should be allowed to serve as aldermen in the Brisbane Municipal Council.