Mark Duffield was hired as Penn State New Kensington's Head Men's Soccer Coach in November 2017. Duffield is originally from Chichester, West Sussex in England and first came to the United States in 2007 with coaching company Challenger Sports. He coached up and down the east coast before coming to Pittsburgh in 2011.  

In Coach Duffield's first season he led the team to a 8-6 overall record going 6-3 in conference, losing in the Conference Semi Final. 2019 saw an improvement going 7-2 in conference but again losing in the semi final. 

With no season in 2020, the team produced a historic year in 2021 reaching the National Championship for the first time in program history. The team went 8-2 in conference play with a 12-7 overall record. Freshman Jacob Guerrini was named USCAA First Team All American and Senior Brady Braun PSUAC Defensive Player of the Year.  

It's not just on the field where the team has found success under Duffield's leadership, many players have received All American and All Conference Academic Awards. In 2019 Benjamin Midlik was honored as the National Division II Student Athlete of the Year by the USCAA. 

In 2012, he was appointed Head Coach of the Highlands High School Girls Varsity team. In his first season, he led the team to a program-best record of 15-4-0 after they previously went 8-10-0. Over 5 years at Highlands, his record was 54-29-4. Along the way, the team won its first playoff game in school history, beating previous champions Montour, and reaching the semi-finals in his final season (2016).  

Duffield spent the 2014 season with Penn State New Kensington as an assistant coach under Jordan Valentine. During that time, Duffield was responsible for goalkeeeper training. 

Duffield is the Director of Goalkeeping for Hotspurs Soccer club and a coach at the College Prep Phase, previously being in the Youth Development Phase. He joined Hotspurs in 2013 and has lead his teams to many tournament championships. He also led the 99/00 boys to the State Cup semi-finals. Duffield is was part of the PA West Olympic Development Program staff from 2013 - 2020. He is also the Assistant Coach/Goalkeeper Coach for Hotspurs First Teams that play in the National Premier Soccer League (Men's) and United Women's Soccer (UWS). In 2023, the men's NPSL were the conference champions regional finalists, top 8th in the nation, and qualified for the open cup.

As a player Duffield played goalkeeper, representing his school and county (state). He also spent time on professional teams Portsmouth FC Youth and Crawley Town. After leaving Crawley, he played on a number of semi-professional teams in England. He spent a season playing for Parsippany Blues in New Jersey while coaching in the area.

Duffield holds a USSF National C, NSCAA National Diploma, NSCAA Advanced National Goalkeeper Diploma, UEFA C Goalkeeper License, Futsal Level 1 and a UEFA B License. 

In 2020 Duffield was appointed Athletic Recruiter Co-Ordinator for Penn State New Kensington.