The aim of the Inter School Christian Fellowship (ISCF) is for students to know Christ and make him known. Students are actively involved in running this group and the activities include:
- A weekly lunch time meeting on Fridays, when a student leader gives a Bible talk and prayer, combined with various other activities. Guest speakers from various Christian organisations give presentations at least once every term. There are around 120 students who attend weekly.
- Leaders' planning meeting on Tuesday afternoons when around 15 to 20 student leaders from Years 10-12 meet to plan the next Friday meeting and other activities. They also do a Bible study usually based on the passage that will be spoken about at that next week's meeting.
- Focus groups - or Bible study discussion groups - are run by the student leaders for various year and gender groups through the week at recess and lunch time.
- Annual carol service is held toward the end of the school year as a Christmas celebration attended by the whole school. The students sing carols led by the leaders.
- End of term activity is held on the last day of each term after school and involves students participating in exciting activities which usually involve some games the student leaders have designed themselves.
- Annual house party is held in December where the group goes to a camp for a weekend to hear talks, undertake Bible studies and participate in recreational activities, both formal and informal. More often than not, the speaker is an ex-student of James Ruse. This event is organised and run by the outgoing Year 12 leaders.
- Train and Plan days are held for the leaders in the holidays to map out the activities and responsibilities for the next term as well as covering leadership skills.