Besides teaching, Johnstone has been a member of the Ethics in Research Committee of Queen Victoria Health Care Center, Melbourne from 1978 to 1981; a co-researcher at the Long Term Study of End State Renal Disease, funded by Department of Human Services, U.S.A. from 1985 to 1986; a member of ARCIC II, for the composition of the document on Moral Theology, Life in Christ, from 1990 to 1994; Chaplain at Clinica del Sacro Cuore in Rome, a hospice for cancer patients, from 1986 until 2005; and on a number of occasions a participant in Congress of the Pontifical Academy for Life.
