In his youth, Sam showed an interest in individual sports and activities, such as swimming, karate, and BMX bike riding.

In 2007, while riding a BMX bike on a family holiday in Coffs Harbour, he had an accident that left him a C6 quadriplegic.

[5][6][7][8] While in rehabilitation, he was visited by a school friend's sister, fellow Paralympian, Jemima Moore, who encouraged him to explore para sport.

[5] With six months between him and the 2012 London Paralympics, Sam was determined to recover, get back to training and represent his county.

[10] Just after crossing the finish line for the T52 100m finals, Beat Bösch mistakenly drifted into his lane and crashed into him.

A medical team attended to him and due to health concerns and a concussion from the crash, Sam withdrew from the upcoming 400m event.

[11] McIntosh was one of three Geelong Para Athletes, as well as Martin Jackson and Jemima Moore, to be selected for the Championships.

[12] At the 2019 World Para Athletics Championships in Dubai, UAE, he finished third in his 100m T52 heat, pushing him through to the finals where he placed sixth with a time of 17.69s, tying his season best.