Saudi state television on Thursday interrupted its regular programming to announce the capture of Fares bin Ahmad bin Shwail al-Zahrani.
"Security forces ... were able on Thursday evening to capture one of the heads of strife and bombings," said a ministry official in a statement.
The official said another person was arrested with Zahrani, but his identity would not be disclosed for "the sake of national interest".
A Dubai-based television channel said Zahrani, 27, surrendered to security forces "without putting up any resistance" in a park in the southern Abha region after a chase of several hours.
Zahrani figures on a 26-strong most-wanted list issued by Saudi authorities last December. His capture brings down to 11 the number of anti-government fighters on the list who remain at large.
Others have either been killed in clashes with security forces or have surrendered to authorities.
In mid-June the security forces killed the local chief of the al-Qaida, Abdul Aziz al-Muqrin. He was killed with three of his associates in Riyadh on 18 June.
Zahrani is among the anti-government fighters who spurned a one-month amnesty offered by King Fahd on 23 June to turn themselves in.
Only six fighters took up the pardon offer and just one of those figured on the most-wanted list.