In September 1970, the student body moved into the new building (located on Horseneck Road), built on what was formerly The Sunset Dairy Farm, a.k.a.

The auditorium of the High School is named in honor of Dr. Robert O. Stafford, who was raised in the township and was a long-time teacher and administrator at MTHS.

Prior to the NJSIAA's realignment that took effect in the fall of 2009, Montville was a member of the Suburban Division of the Northern Hills Conference.

[28][29] The 2007 Mustang baseball team defeated Northern Valley Regional High School at Old Tappan, 9–7, to take the North I Group III section title for the first time since 1989.

[33] The girls' lacrosse team won the overall state championship in 1984, defeating Moorestown Friends School in the tournament final.

[34] The girls tennis team won the Group III state championship in 2013, defeating Princeton High School in the tournament final.

[37] In 2009, the Montville boys' soccer team tied Madison High School 0–0 in the final of the Morris County tournament.

[38] The Mustangs went on to win their third ever sectional title, beating Northern Highlands Regional High School 2–0 in the final.

[39] In 2010, Montville captured the Morris County boys' soccer title outright, winning 1–0 in overtime against Chatham High School.

[42] In 2003, the Montville Mustang football team set school records with nine wins and six shut outs, winning the first round of the state sectionals before losing in the state semi-final game, earning induction into the Montville Township Hall of Fame in 2011.

[48] The school's marching band won the USBands Group III A national championship in 2015 with their program Equilibrium.

[50] The school's marching band won the USBands Group II-A national and state championships in 2018 with their program Elements.