The 41-year-old, who live-streamed the incident where he allegedly entered Spears’ wedding venue, was arraigned at Ventura County Superior Court earlier this week.
Alexander – who was married to the singer for 55 hours in 2004 – had been charged with stalking as well as four misdemeanors that included battery, trespassing, and vandalism.
Speaking to Page Six, Ventura County Senior Deputy District Attorney Erin Meister confirmed this week that Alexander entered a not guilty plea on all counts.
He appeared at the arraignment hearing from jail via Zoom.
His next hearing is reportedly scheduled to take place on August 2.
Alexander currently remains in jail, with bail set at $100,00 (£84,500).
Ventura County District Attorney’s office has been approached by The Standard for further comment.
At the start of June, Spears finally married Sam Asghari at a lavish ceremony at her California home.
On the day of the A-list event, Alexander live-streamed on social media as he allegedly gained access to the event by bypassing security before he was stopped.
In the video, Alexander could be heard saying he was “here to crash the wedding”.
Following her wedding, Spears was granted a restraining order against Alexander.