All-American high school guard Reggie Jackson signed a national letter of intent yesterday to attend Maryland.

Before his name appeared on the dotted line at 3:01 p.m., Jackson surprised a small gathering of media people in the library of Roman Catholic High School by talking frankly of Maryland's problems and volunteering himself for the Terapins' most needed and unfilled role: team leader.

"I felt they didn't play well together," said Jackson.

What was their problem, someone asked.

"Selfishness," Jackson said clinically. "That's one of them.

"There will be a lot of changes - that's the way I feel. They need better ball movement, more team play. The mosy important thing is that desire to win, to have it inside you. I felt that the mistakes they were making were ones I didn'tmake.

"We'll have to be more friendly off the court; be a family, love each other. "I would like to be a leader. Maybe I can demonstrate unselfish, team play.Maybe the juniors and seniors might notice it and look up to me. I feel like it will be an easy adjustment for me because I want it so bad."

jackson, 6-4, is one of those rare people who manages to exude confidence without being cocky. After the press conference, his high school coach, Speedy Morris, told Jackson responded without hesitation.

Besides being regarded as one of the top five high school guards and one of the top 10 players in the country, Jackson has good grades (his average at Roman Catholic has fallen to C-plus during his hectic senior year). He is a product of a disciplined doctrine at home, in the classroom and on the basketball court.

Last year was the year of the forward in college recruiting, but 1978 produced a crop of exceptional guards. The best were Jackson, Dwight Anderson of Roth High School in Dayton, Ohio (signed with Kentucky); Vince Taylor of Tates Creed High in Lexington, Ky. (signed with Duke); Darryl Mitchell of North Shore High in West Palm Beach, Fla., and Greg Goorjian of Crescenya Valley High in La Crescenta, Calif. There is no real consensus as to who is the best.

Jackson is a skilled all-around player, well-versed in fundamentals by Morris, whose 11-year coaching record at Roman Catholic is 261-66. Roman Catholic, a school of 913 boys in central Philadelphia, has a rich basketball tradition over its 88 years.

Only one Roman Catholic graduate appears on a pro roster - Mike Bantom of the Indiana Pacers - but as far back as the 1920s the school that requires daily wearing of ties gained fame with a group known as the Mightly Mites, who won three straight city titles. A Roman Catholic team that some consider among the best in high school history won the Philadelphia title in 1974. This season, the hillites (named after the founder of the school) posted a 32-4 record, losing the city title game to West Philadelphia.

Jackson holds virtually every important Roman Catholic record: career points (1,861), career scoring average (18.6), and single-Season scoring average (21.6 in 1977-78). On the list of most points scored in a game, Jackson is first with 41 points and other performances rate him second, third, seventh, eighth, ninth and 10th. He had 130 assists last year.

Hackson's father, Reginald, who works for the city as a crane operator, and his mother, Dot, a nurse in a hospital for the handicapped, sent their only child to Roman Catholic because the father said, "We felt children need some discipline at school as well as at home. We'd seen the problems youngsters were having."

The temptations of city life were available to Jackson, but the articulate, carefree youngster says he rejected them "because I was in the school yards I had one thing on my mind."

Jackson showed an interest in basketball, his mother recalled, "when he was a little tyke in shorts, 4 years old. I wanted to buy him something nice for Easter, and he wanted a basketball. I tried to talk him into something else, but he wanted that ball."

Although he enjoys other sports, Jackson never played anything but basketball on the varsity level, and Maryland Coach Lefty Dreisell discovered and recruited him seemingly before anyone else - in the summer after Jackson's sophomore year. Several Catholic schools were playing in the Alhambra-Cumberland invitational tournament in Cumberland and, after seeing him there, Dreisell and his staff have, according to Jackson, "shown way more interest than anyone else."

"He really wants me. And he has me."

Jackson was interested in Duke and it is unclear who rejected whom ultimately in that affair. But it was over when Duke signed Taylor.

Jackson narrowed his choices from 200 interested schools to Maryland, Villanova, Penn State and Detroit. He made his final decision Sunday night after returning from a trip to Penn State. Villanova was his second choice, Penn State third.

Jackson's father recalls once receiving a letter from Driesell that said in part, "Reggie, we want you here at Maryland to run our offense after Brad Davis leaves." It is believed Jackson will take over at point guard, and that Greg Manning will be moved from there to the other backcourt spot.

The signing cast further question onthe return of Maryland guard Jo Jo Hunter. While Hunter said last week he would return next year, rumors persist that he is looking elsewhere. Guard Billy Bryant has joined a campus fraternity and appears to be happier than he has been in some time.

Among other things, the fraternity requires Bryant to study in th library from 7 until 11 p.m. and Bryant, who is having some academic problems as well as Basketball difficulties, says the fraternity has helped him immensely and that he definitely wants to continue at Maryland next year.

One of the first people to call Jackson and congratulate him was Reggie Henderson, who is the coach of a high school forward Driesell wants badly - Buck Williams of Rocyk Mount, N.C.

Asked about his conversation with Henderson, Jackson said, "I think it (his signing) might have a little influence on Buck. The whole thing is to get those pieces of the puzzle together." William, a 6-8 forward, has said he will decide Monday where he will go. The choice is apparently between Maryland and North Carolina.

Jackson said he looked at Maryland's problems "in a positive way. They need a guard and I feel I could be one of the People to lift them back up. I think the first year will be the toughest, but I'll be okay. I love challenges. I can't wait to go."

Morris has called Jackson the best player ever to don Roman Catholic's purple uniform.

"He can do everything," said Morris. "He takes pride in passing the ball.

Choosing a school. We considered the coaching staff, we wanted a running stule of play that would prepare him for pre ball, a location that was close enough to Philadelphia so that his parents could see him play, and academics. He liked the coaching staff so much, and it intrigues Reggie to try and help build the program back up to where Lefty had it a few years ago. That's the type of kid Reggie is."