He was a cast in Ang TV 2 (as JM "Butik" de Guzman), where his batchmates include Shaina Magdayao and Denise Laurel.

In 2007, he won a silver medal for Quezon City during the Philippine Olympic Festival – National Capital Region qualifying round.

After a two-year hiatus, ABS-CBN promoted de Guzman's return starting December 6, 2017, before signing his contract to Star Magic.

In 2018, he was cast as leading man in PHR series Araw Gabi and paired with former Girltrends member Barbie Imperial who has been claimed having a strong chemistry with him, form a loveteam called "JuanBie" by fans.

On November 11, 2018, he interpreted Sa mga Bituin na Lang Ibubulong for Himig Handog 2018, composed by Kyle Raphael Borbon.

He joined The Iron Heart in the second season as Brother Joseph Cruz, the religious leader of Yusebeia, one of the main antagonists-turned-protagonist of the series.

[5] The premature cancellation of his show Angelito: Ang Bagong Yugto was said to be caused by De Guzman's eventual erratic behavior on set.

In late 2014, after De Guzman's completion of his rehabilitation and a hiatus for over a year, he made a showbiz comeback and rekindled his relationship with Mendiola which lasted for 5 months before breaking up for the second time.

[6] His reported problematic attitude on the set of the 2015 Metro Manila Film Festival entry Walang Forever led to his replacement in the movie by actor Jericho Rosales.