He turned down a walk on offer to University of San Francisco to continue his basketball career at the community college level.

Selected Co-Most Valuable Player of the Coast to Conference North in 2006–07 for Coach Justin Labagh and the CCSF Rams, who were ranked No.

"[2] Marcio provided an offensive spark off the bench as well as a strong defensive presence on the wing during the 2007–08 season, playing in 32 of the team's 33 games.

Transferee from San Francisco City College averaged 3.3 points and 1.0 rebounds and showed the ability to score in bunches.

The combination of Casio, Lassiter and David also beat the Yeng Guiao-led Rain or Shine Elasto Painters in the semifinals in seven games.

On April 20, 2012, the Philippine Basketball Association approved the trade in which Powerade sent Marcio Lassiter and Celino Cruz to the Petron Blaze Boosters for Rey Guevarra, Rabeh Al-Hussaini, and Lordy Tugade.

On November 14, Lassiter recorded his first double-figure scoring output with 12 points to go along with 2 rebounds in 21 minutes of playing time on a 96–86 win over the Rain or Shine Elasto Painters.

In the 2014–15 Philippine Cup, Lassiter helped San Miguel win its twentieth franchise title after defeating Alaska in a hard-fought seven-game series.

The following game, Lassiter has a woeful shooting night, only scoring 6 points on 2-for-10 (.200) from the field but the Beermen manages to win over the Purefood Star Hotshots, 100–89.

[6] On July 2, 2015, Lassiter scored 22 points, grabbed 7 rebounds and made 4 3-pointers as the Beermen got Game 1 of the 2015 PBA Governors' Cup Semifinals against the Rain or Shine Elasto Painters.

[7] On July 4, Lassiter got his career high of 10/13 3-point shooting for 31 points in a losing effort against Rain or Shine in game 2 of the semifinals.

[8] On September 15, 2024, Marcio Lassiter officially broke the record of all-time three-pointers made previously owned by Jimmy Alapag.

[9][10] As of the end of 2023–24 season[11][12] With Lassiter playing for Smart Gilas, he was a member of the Philippines men's national basketball team that was bannered by collegiate and amateur standouts whose ultimate goal was to reach the 2012 London Olympics.

He has an older brother named Jolinko who is the Boys' Varsity Head Basketball Coach at George Washington High School in San Francisco.

He currently lives in Manila with his US-born Filipina wife, Jerlyn Lassiter (née Pangilinan) and their four young sons, Montaé Izaiyah, Myles Elaijah, Marcel Josaiah and Melo Zekaiah.