"I am disappointed to have fitness problems which forced me to return from the Australian tour in the last phase but you can't say my tour was disappointing," Akhtar told AFP on return on Saturday.
The 29-year-old pace bowler injured his hamstring in Pakistan's tri-series match against the West Indies last week and needs to prove his fitness to selectors ahead of next month's tour of India.
"I played the Sydney Test with injury, otherwise I took eleven wickets in the first two Tests which was not disappointing, and because of my fellow pacer Mohammad Sami also falling injured, our bowling failed in the last Test."
"We caught Australia 78-5 in the first Test and 170-5 in the second but let them off. Captain Inzamam-ul Haq's injury which prevented him from playing in the last two Tests was also a major setback."
He admitted his regular breakdowns with injury would harm his reputation.
"I know I have to raise my fitness levels but I assure everyone that I never fall short in commitment," Akhtar said.
Akhtar's fast bowling predecessors for Pakistan, Wasim Akram and Waqar Younis, have both launched attacks on his recurring breakdowns, reportedly saying "an unfit Akhtar is not what Pakistan needed."
Pakistan coach Bob Woolmer, who objcted to Akhtar's lengthy bowling run-up, criticised Akhtar after the Sydney Test saying he was a shadow of himself and everyone was disappointed with his commitment.
"Every fast bowler had injuries and so have I, mine are more because of the load of bowling, but I always try my best," Akhtar defends.
The mercurial pace bowler said he was also disappointed over what he saw as a character assassination campaign by the foreign media.
"I am hurt and this ugly campaign of fabricated pictures on the internet, they rub salt to my injury and I think it is character assassination."
Foreign television channels showed internet pictures of Akhtar with girls in a disco.
"One day a friend came to me in India and protested I did not invite him to my wedding. When I told him I am not married yet he showed me an internet photo showing me as a groom and a girl with me as my bride.
"Even personalities like President George Bush is shown in nasty pictures on the (inter) net but you can't believe all that."
"I am more hurt when my own people back that ugly campaigns."
"All this is done because I am injured. I think this is aimed at putting me under pressure before the all important India tour."
Akhtar said he knew the task in next month's series against India would be more difficult.
"It (India tour) is a difficult task because every Pakistani would like us to win in India. I would regain full fitness and do my best to help my team do well in India."