"I think you should take it immediately. You should have taken it yesterday," Musharraf told ABC News in an exclusive interview.
Musharraf made his comments following the leak of McChrystal's security assessment that called for additional U.S. troops to fight in Afghanistan. In the assessment, McChrystal said more troops alone cannot achieve success "but will enable implementation of the new strategy. Conversely, inadequate resources will likely result in failure."
In February, Obama authorized an additional 21,000 troops be deployed to Afghanistan and now he must decide if the situation requires even more.
Musharraf said he "absolutely" believes there need to be more troops in Afghanistan.
Sending more troops could also mean an increase in casualties, something Musharraf says the United States should be prepared for.
"We must avoid, as much as possible, casualties. But when soldiers move and armies act, casualties will be there, and we should accept casualties," Musharraf said.
"We have to win," the former general said. "And quitting is not an option."
Musharraf even proposed what he called a "drastic" measure to secure the border between Pakistan and Afghanistan.
"As far as I'm concerned, we should mine it so that people can't go across," Musharraf said.
While he acknowledged that mines are a controversial weapon, Musharraf argued that it is an "unusual war."
Musharraf dismissed Afghanistan's long history of defeating foreign armies, including the Soviet army in the 1980s.
"There's always a first time," Musharraf said.
He argued the United States could succeed where the Soviets failed because "the whole world" was helping insurgents fight the Soviets.
At another point, the former Pakistani general said, "It was you who invaded and came into Afghanistan, so you better face it now and win there."
When asked what the consequences would be if the United States withdrew from Afghanistan, Musharraf said it would result in destabilizing Afghanistan. He said the country would become the center of all al Qaeda "sanctuaries" and consequently could extend its influence into Pakistan and possibly even India.
Musharraf said he believes Obama has "intentions of improvement" since taking office.
"He's saying the right things. He wants to focus more on Afghanistan, compared to Iraq, which is the right strategy at this moment," Musharraf said. "He wants to reach out to the Muslims."
Musharraf added that "we need to see [results] on ground."
Returning to Pakistan
Musharraf came to power in 1999 following a military coup and resigned in 2008 amid threats of impeachment after he removed a Supreme Court judge from the bench and imposed emergency rule on the country.
The former president said he "will return to Pakistan" despite the possibility of facing trial as soon as he sets foot in the country.
"Well, these are realities which one has to face. But however, I am very sure of one thing -- that whatever I have done till now, constitutionally and legally, there is no charge against me," Musharraf said.
Return to Pakistan
When asked if he would try to return to power, Musharraf would not answer the question directly.
"Well, I give thought to what is happening in Pakistan. And I give thought to what the people of Pakistan are desiring, and I also give thought to whether I can do anything for Pakistan," Musharraf said. "Collectively, I have to make a decision based on all these three elements."
The former general, who is currently living in exile in London, is prohibited by law from running for political office until this December, two years after he took off his military uniform.
Should Musharraf decide to return to politics, he likely would face Nawaz Sharif, a political opponent and someone the former president called "abrasive" and confrontational.
"He has never been on good terms with any president of Pakistan, so I don't know what kind of a mental make-up he has. But the man is abrasive against the other power brokers of Pakistan," Musharraf said.
The former general even went so far as to call Sharif a "closet Taliban."
"Even on Pakistan television these days, talk shows are going on saying that he has met Osama bin Laden five times -- five times before 9/11 -- and he has been financed by Osama bin Laden," Musharraf said. "Then the other element is that he never speaks against terrorism and extremism."
But when pressed for proof of Sharif's meetings with bin Laden, Musharraf said he personally could not offer any.
"No, I can't do that, but there are certainly there are people who vouch for it, who were present there," Musharraf said.