Fagan announced on Friday he was resigning in December, just months after signing a new one-year contract to lead the Brumbies into the future.

It continues the Brumbies' turbulent off-season which was triggered by coach Jake White's decision to quit the last two years of his contract despite lifting the team to the top of Super Rugby.

Losing a chief executive and World Cup-winning coach is a massive and unexpected leadership overhaul for the Brumbies following their rise into the Super Rugby final.

Fagan was in contention for a cross-code switch to the Canterbury Bulldogs earlier this year and was interviewed to replace Todd Greenberg.

There is also speculation linking Fagan to the NSW Waratahs or a move to the NRL in the coming months.

Fagan insisted he had not decided on his future and he had no job to start at the end of his Brumbies tenure.

Quitting the Brumbies allows Fagan to negotiate openly with potential employers.

''It makes sense to [leave the Brumbies] now, I've been thinking about it for some time and in many respects I've been thinking about it for four years,'' Fagan said.

''I think the organisation could do with some fresh eyes and I could do with some fresh challenges.

''I agreed to extend for one final term, but the way the things have panned out this year … this is a much better time to depart the organisation.

''I do so with a heavy heart, but excited about the future. I've been presented with a number of opportunities but I haven't been able to pursue them because of my commitment with the Brumbies.

''I look forward to exploring those in the new year.''

Fagan informed the board on Thursday he was resigning.

No interim chief executive has been appointed and chairman Sean Hammond said the Brumbies were in no rush to find a replacement, even if the club starts the 2014 Super Rugby season without a boss.

Australian rugby and Brumbies great Joe Roff, who is on the Brumbies board, has emerged as one of the front-runners.

The Brumbies have also secured the University of Canberra as a major sponsor for the 2014 season and an announcement about the partnership renewal is expected in the coming weeks.

Stephen Larkham has replaced White as the head coach while Laurie Fisher is the club's new director of rugby.

Fagan started at the Brumbies as general manager in 2002 and was promoted to chief executive in 2005.

''A December finish is better, it allows the new chief executive to come into an organisation that's in good shape,'' Fagan said.

Fagan has overseen massive changes at the Brumbies since taking charge as chief executive.

He helped the Brumbies through heartache when player Shawn Mackay died in South Africa in 2009.

''There are some moments I'll reflect on with sadness, times like Shawn Mackay those times were tough,'' a teary Fagan said.

''I've seen some great things, I've been here when we won championships and I'm proud of where the team is now. At times decisions weren't popular … but they've been for the better of the organisation.''

He endured controversy to get ACT government approval for a $30 million, 130-apartment complex to be built at the club's Griffith headquarters.

The Brumbies will also move into a new $15 million home at the University of Canberra at the end of March.

Fagan stepped in to sack coach Andy Friend after just two games in 2011 and the Brumbies experienced the lowest ebb of their history following the decision.

However, he recruited World Cup-winning coach White to lead a revival.

The Brumbies narrowly missed the final in White's first season in 2011 and then charged into the Super Rugby final this year, losing in a heart-breaking decider to the Waikato Chiefs.