He attended the University of Sydney from 1966 to 1968, where he received a Bachelor of Science (Pure Mathematics), and joined the Liberal Party on 14 March 1967.
His most prominent position was as Manager of Public Affairs for the Electricity Association of New South Wales, 1988–95.
[1] In 1996, the Liberal MP for the local state seat of Strathfield, Paul Zammit, resigned to contest the Australian House of Representatives.
Although the margin was still notionally Liberal, MacCarthy was resoundingly defeated by Ashfield Labor MP Paul Whelan.
[3] After his defeat, MacCarthy worked as a part-time member of the New South Wales Election Funding Authority until 2003.