"He was always so good looking and he was always a standout," Adrian Harris Forman, a former classmate at Longview High School in east Texas, tells PEOPLE.
Voted "Most Handsome," the athletic, charismatic teenager "was always the cutest guy, and there were a lot of cute guys in Texas," says Forman, director of development at Family-to-Family.
"We were all in Cotillion together and we would take ballroom dancing. The boys would have to wear a jacket and tie and they had to learn how to ask a woman to dance. Matthew was always so charming."
But he had more than just good looks going for him: popular among his peers, "he always loved hanging out and was a fun guy to be around," says Forman, noting that he also excelled on an academically advanced track.
McConaughey's natural charm echoed that of his mom (and future Oscar date!) Kay, now 82, a school teacher.
Leah Pickett / Splash News Online
Although he had not yet coined his signature "Just Keep Livin' " attitude, it was clearly in the formative stages even during high school.
"I remember once we had a huge shaving cream fight with Barbasol shaving cream," says Forman. "He loved to have fun."
Reporting by ELIZABETH MCNEIL
For much more on McConaughey's journey – and a closer look at his evolution from Texas teen to romantic comedy king to Oscar champ – pick up this week's issue of PEOPLE, on newsstands now