As point guard, he was part of the NCAA Division III tournament teams in 1974-75 and 1975–76, and held the school's single season and career assist marks (421) at the time he graduated.

He continues doing charitable work in the Norristown community, decades after his high school coaching days ended there.

[8][9][10] Martelli began his career on Hawk Hill with SJU's 1985-86 NCAA Tournament team, as an assistant coach under Jim Boyle.

[13] In his second year, under the floor generalship of Junior point guard Rashid Bey, and help from Arthur "Yah" Davis, Terrell Meyrs, and Dmitri Domani, Martelli's Hawks captured the Atlantic 10 (A-10) crown and made it into the Sweet Sixteen round of the NCAA tournament.

The Hawks lost to Xavier in the Atlantic 10 Tournament, and reached the Elite Eight, ultimately losing to Oklahoma State 64–62, to finish with a record of 30–2.

[32] In 2014, the Hawks returned to the NCAA Tournament after winning their second Atlantic 10 Championship under Martelli, led by Langston Galloway, Ronald Roberts and Halil Kanacević.

[38] In December 2011, Martelli was referenced in an article on SI.com in which former player Todd O'Brien detailed his side of a story about his former coach holding a grudge.

[39] With a win against Morgan State in 2011, Martelli became the all-time winningest coach in Saint Joseph's history with his 310th victory, passing Billy Ferguson.

[40] On October 25, 2015, Saint Joe's announced that Martelli received another contract extension (though the terms of the deal were not immediately released).

On March 19, 2019, Director of Athletics Jill Bodensteiner announced that the university had let go of Martelli, ending his 24-year tenure as head coach.

Martelli has also lost more games than any coach in Saint Joseph's history, eclipsing Bill Ferguson's 208 losses in 25 seasons.

[60] Martelli is close friends with long time University of Connecticut women's basketball coach Geno Auriemma.

His son, Phil Jr., has served as the head coach of the Bryant University men's basketball team since November 15, 2023.

[61] His other son, Jimmy, serves as an assistant coach on the Penn State University men's basketball team.

[28] Martelli served as chair of the Coaches vs. Cancer National Council for 12 years, and as the co-chair of the Philadelphia chapter of that organization.