Selma has rapidly become more known in Hollywood circles, amassing some nice career credits. The recent boom in teen programming - both on television and in theaters - benefitted many young stars, but Blair seems to be one of the few with the savvy and sophistication to take full advantage of it. She appeared in the 1998 USA Network TV-movie "No Laughing Matter" before landing a role in the ensemble of the teen comedy feature "Can't Hardly Wait" (1998). Blair had her first starring film role in the thriller "Brown's Requiem" (1998) and was chosen to head the cast of the coming-of-age midseason replacement series "Zoe, Duncan, Jack & Jane" (The WB, 1999-2000), playing Zoe Bean, a witty and blunt Manhattan teenager. She was also tapped for the role of shy Cecile in "Cruel Intentions", a contemporary reworking of "Les Liaisons Dangereuses" set in New York starring Sarah Michelle Gellar and Ryan Phillippe, and was featured in the music-themed "Girl" (both 1999).

2001 saw her return to the big screen with a memorable supporting role as an uptight Harvard Law student in the hit comedy "Legally Blonde". Then in 2003, Blair joined Jason Lee and Julia Stiles for the romantic comedy "A Guy Thing." She once dreamed of being a successful New York photographer, but she has found most of her success on the opposite side of the lens.