One year later, at Pro Tour London 1999, he got his major breakthrough by making the top 8, ultimately finishing 6th, losing to eventual champion Kyle Rose.

[7] The 2000–01 Pro Tour season started with Jensen winning the inaugural Masters event, beating among others eventual Hall of Famers Nicolai Herzog, Olivier Ruel, and Bob Maher en route to the title.

In the finals, they faced the Norwegian team 'Unoriginal Slackers', where Jensen won his match 2–0 over Jake Smith.

[6] In 2012, despite not having played a professional event in almost eight years, William Jensen was among the top candidates for getting voted into the Hall of Fame.

He eventually missed by a single vote,[13] but received a special invitation to play at Pro Tour Return to Ravnica.

At the 2014 World Championship, Jensen came close to reaching the top 4, but lost the last round of Swiss to Yuuya Watanabe, resulting in an 8th-place finish.

[20] He finished the season on 47 points, enough for Platinum status in the Pro Player Club, but not enough to qualify for the 2015 World Championships.