Brownless was born and raised in Jerilderie, a rural town in New South Wales. He first played football for his local team, the Jerilderie Football Club, when it was part of the Murray Football League. He boarded for three years in Kilmore, Victoria, at Assumption College, one of Australia’s most renowned “football nurseries”, a school which has a strong tradition of producing footballers who have gone on to play in the AFL. In 1984, his final year at the school, Brownless kicked 155 goals for the school team.

Brownless first played State of Origin in 1988 for New South Wales. Playing in the State of Origin Carnival that year, he kicked three goals in the tournament, two in the first against South Australia and one in the second against Western Australia. In 1993 he again played in the State of Origin Carnival, being selected for NSW/ACT against Victoria. With Wayne Carey and John Longmire in the side, Brownless played at centre half back. In 1995 he kicked five goals and was named in the best players for Allies in a win over Western Australia.

In 1992 he became the inaugural winner of the Mirrool Silo Kick in the Riverina, kicking an Aussie Rules football 32 metres plus over the Mirrool Silos.

One of Brownless’ fondest memories was kicking a goal after the siren against Footscray in their 1994 qualifying final. With Geelong trailing by one point, he marked the ball within scoring range with just seconds left and kicked a goal to send Geelong through to the next stage of the finals. While the Cats eventually made it to the grand final, they lost that match. Brownless played in four losing grand final teams with Geelong.

Brownless “retired“ in 1997 at 30 years of age, although the reason for the retirement was because he wasn’t required at the club for the 1998 AFL Season.

In August 1999, it was reported that due to Brownless’ connections in the local political scene, both the Australian Labor Party (ALP) and the ruling Liberal Party of Australia were keen to recruit Brownless into politics, despite his limited experience. Labor leader Steve Bracks, who would go on to win the state election that year, was a Geelong supporter, and Brownless had persuaded the then Premier Jeff Kennett’s wife, Felicity, to become Geelong’s female number one ticket holder.

By 2005, Brownless had featured on The Sunday Footy Show as well as earning continual appearances on The Footy Show. He also co-hosted Morning Glory, a weekday breakfast show on Melbourne radio station SEN 1116. Brownless finished his 5-day-a-week stint in November 2008. Brownless appeared on Before the Bounce, a weekly football show on Foxtel alongside Jason Dunstall and Danny Frawley until the end of the 2008 AFL season.

In May 2008, Brownless was added as a regular on the Thursday night AFL Footy Show to replace an incapacitated Sam Newman, but he was relegated to guest panelist upon Newman’s return. From 2009 until the show’s termination in 2019, Brownless had once again become a regular alongside Shane Crawford to replace Trevor Marmalade, alternating each week with Crawford and, since 2012, Matthew Lloyd.

In March 2010, Brownless joined Triple M Melbourne’s new drive show The Rush Hour with James Brayshaw.

Brownless was married to Nicky. They have two daughters, Lucy and Ruby, and two sons, Oscar and Max. Brownless and Nicki made headlines in 2016 and beyond after it came to light that they had separated after 18 years of marriage in 2015 and that Nicki had proceeded to have a relationship with one of Brownless’s colleagues, Garry Lyon, which caused a bitter falling-out between Brownless and Lyon, including causing Lyon to leave the show with depression.

In January 2020, Brownless appeared in the sixth season of the Australian version of I’m a Celebrity…Get Me Out of Here!.