In addition, Cahill is a tennis analyst for the Grand Slam events on the US sports network ESPN and a coach with the Adidas Player Development Program and at ProTennisCoach.com.

Cahill's best singles performance at a Grand Slam event came at the 1988 US Open, where he knocked out Lawson Duncan, Boris Becker, Marcelo Ingaramo (a walkover after Ingaramo withdrew), Martin Laurendeau, and Aaron Krickstein on the way to reaching the semifinals, where he lost to eventual champion Mats Wilander.

In 1989, Cahill finished runner-up in men's doubles at the Australian Open partnering fellow Aussie Mark Kratzmann.

Cahill was a member of the Australian team which reached the final of the Davis Cup in 1990.

Cahill compiled a 6–4 career Davis Cup record (4–0 in doubles and 2–4 in singles).

[3] After chronic knee injuries and ten operations, he retired from the professional tour in 1995.

[3] Since retiring from the tour, Cahill has been a successful tennis coach and guided Lleyton Hewitt to become the second youngest player ever ranked world No.

Cahill joined the Adidas Player Development Program after Agassi retired in 2006 and has worked with high-profile players, including Andy Murray, Ana Ivanovic, Fernando Verdasco, Daniela Hantuchová, Sorana Cîrstea, and Simona Halep.