Continuing in Australian Formula 3 in 2005, Alajajian started the year with Astuti Competition, before moving to Protecnica Racing.

He scored a podium at Queensland Raceway and was involved in Mark Porter's fatal crash at Bathurst later in the season.

He continued in the Fujitsu V8 Supercar Series 2007, claiming his only race win at the second round at Wakefield Park Raceway.

[3] In August 2007, Alajajian tested for A1 Team Lebanon in the A1 Grand Prix series at Snetterton Circuit.

Alajajian finished runner-up in the Australian Mini Challenge in 2009 and won the championship in 2010.