He either being obnoxious in Saudi Arabia, or fighting the USSR in Afghanistan:

Who is Osama Bin Laden?

The USSR invades Afghanistan: 1979

When the Soviets invaded Afghanistan in 1979, he went to Pakistan, where he met the Afghan rebel leaders fighting against the occupation.

When he returned he collected money and supplies for the Afghan resistance, the mujahedin.

He made further trips, delivering aid and arms, spending more time in Afghanistan, where he became involved in gun battles with the Soviets.

Oliver North Trial: 1988-1989

The USSR pulls out of Afghanistan: 1989

Never a wholehearted supporter of the Saudi regime, Osama bin Laden became an out-and-out opponent and began to direct his efforts against the US and its allies in the Middle East.

In 1991 bin Laden was expelled because of his anti-government activities.

He spent the next five years in Sudan, where he used his money to fund a number of infrastructure projects for the Islamist government in Khartoum.

The Saudi Government is said to have sought reconciliation, but when this failed, it froze his bank accounts and stripped him of his Saudi citizenship.
(BBC History Source “Who is Osama Bin Laden?”)

Dan