Career honors
- Honorable Mention All-American - 400 IM (2007)
- First Team All-American - 400 IM (2006)
- Big Ten Champion - 400 IM (2006, 2007)
- First Team All-Big Ten (2006, 2007)

Summer 2007: Kaitlin had arguably the best summer season of any member of the women's swimming team as she swam in five events and excelled in all of them. At the Eric Namesnik Memorial Grand Prix, she finished seventh in the 200 breaststroke, 12th in the 200 IM and third in the 400 IM. She followed that up by placing in the finals of four events at the Charlotte Ultraswim of the Grand Prix series, finishing 21st in the 400 freestyle, second in the 200 breast, seventh in the 200 IM and fifth in the 400 IM. At the Mid-Atlantic Senior Championships, she was fourth in the 200 breast, seventh in the 100 butterfly, second in the 200 IM and fourth in the 400 IM. At U.S. Nationals, she placed sixth in the 400 IM and seventh in the 200 breast in addition to 20th in the 200 IM. That performance qualified her for the U.S. National Team for the Japan International Grand Prix in Chiba, Japan. There, she finished 10th in the 400 IM, 15th in the 200 breast and also swam in the 200 IM.

2006-07: Kaitlin successfully defended her Big Ten title in the 400 IM at Big Ten Championships as a sophomore, becoming the first Penn State swimmer to repeat as a Big Ten champion in the same event since Kristen Woodring won the 100 breaststroke in both 2004 and 2005. For her performance, she was a first team All-Big Ten selection for the second straight year. Kaitlin also scored points in the 200 IM with a fourth place finish and the 200 breaststroke with a sixth place finish at Big Ten's. After her performance at Big Ten's and her NCAA `A' qualifying time in the 400 IM and `B' cuts in both the 200 IM and 200 breast during the season, she made her second straight trip to NCAA Championships, where she swam her career bests in both the 200 breast and 400 IM and became an honorable mention All-American by finishing ninth in the 400 IM, just narrowly missing out on a top eight finish. By swimming her career best time in the 400 IM, she also lowered her own school record that she had set as a freshman. Heading into NCAA Championships, she had won an amazing one-third of her individual races during the season (10 out of 30) and for the year had a total of 12 first place finishes, including two in relay events. She also had two second place finishes and had the top times on the team for the year in the 400 IM and 200 breast and the second-fastest time on the team in the 200 IM. Additionally, she also swam an NCAA `B' cut in the 1650 free in her first career swim in that event.
Meet-by-Meet Highlights: Placed second in the 1000 free, fourth in the 200 breast and was on the fifth place 400 free relay team at the dual meet at West Virginia....Won the 200 breast in her fastest time of the year and also swept both IM events, winning both the 200 and 400 at the Clemson/Virginia/Virginia Tech/Penn State quad-meet....Finished fifth in the 200 fly and third in the 200 IM at the Big Cat Invitational....Picked up points for Penn State in the 200 breast (10th place), 200 IM (5th place, 4th in the prelims) and 400 IM (4th place, 1st in the prelims), swimming her fastest times of the year in both IMs at the Bell Grand Prix....Won the 100 back in only her third career swim in the event, placed fourth in the 50 free and was on the first place 200 medley relay team at the dual meet vs. West Chester....Won the 200 free in her first career swim in that event and was just .03 of a second off an NCAA `B' time and also placed third in the 200 back in her first career swim in that event as well in dual meet vs. Ohio State....Won the 200 breast and finished second in the 200 IM in the meet vs. Rutgers....Placed third in the 1650 free with an NCAA `B' cut in her first career swim in that event and also won the 400 IM, finished third in the 200 breast, fifth in the 200 IM and was part of the first place 800 free relay team at the Shamrock Invitational.....Picked up points for Penn State in the 200 breast (6th place), 200 IM (4th place) and 400 IM (1st place) at the Big Ten Championships....Was named first team All-Big Ten after winning the 400 IM for the second straight year.

2005-06: Kaitlin was an All-American as a freshman after finishing sixth at the NCAA meet in the 400 IM. This came after winning the 400 IM title by over three seconds at the Big Ten Championships with an NCAA `A' qualifying and pool record time of 4:12.03. One of 12 swimmers and four freshmen to qualify for the NCAA Championships, she was also named first team All-Big Ten. At the NCAA meet, she also swam in the 200 IM and 200 breaststroke in addition to the 400 IM. In addition to her title in the 400 IM at the Big Ten Championships, she also placed fourth in both the 200 breaststroke and 200 IM with NCAA `B' qualifying times in both events. Including her Big Ten title in the 400 IM, Kaitlin won 10 events during the season, including four 400 IM events and four 200 IMs.
Meet-by-Meet Highlights: Won the 200 and 400 IM as well as the 200 breast in a pool record time of 2:18.56, and also placed fifth in the 100 breast and was on the third place 200 medley relay team at the Indiana/Ohio State/Penn State tri-meet....Won the 200 IM and was on the second place 200 medley relay team in the dual meet vs. Kenyon....Won the 200 IM in the dual meet vs. Rutgers....Finished second in the 1000 free in the dual meet with St. Bonaventure....Won the 1000 free at the dual meet vs. West  Chester....Won the 400 IM and placed fourth in the 200 IM and fifth in the 200 breast in the Auburn/Purdue/Virginia/Penn State quad-meet....Tied for first in the 200 IM and was on the fourth place 200 medley relay team at the Arizona State/UCSB/Penn State tri-meet....Won the 400 IM and placed fifth in the 200 breast at the Arizona/Wisconsin/Penn State tri-meet.

High School: Kaitlin won three New Jersey state titles at Mount Saint Dominic Academy in Caldwell, N.J. Swimming for head coach Andrea Jordan, O'Brien won the 2004 and 2005 200 IM titles and the 2004 500 free crown. She was 500 free runner-up as a senior. O'Brien was the 2004 Junior National Champion in the 1650 free and placed third that year in the 400 IM. O'Brien also swam for the Cougar Aquatic Team and coach Kit Ashenfelter. At senior nationals, she placed 33rd in the 400 IM in 2005 in Indianapolis.

Personal: O'Brien lists reading, movies and being with friends and family as hobbies. She is the daughter of Jane and Jay O'Brien and has a brother, John. O'Brien is majoring in public relations.

Why I Chose Penn State: "The team and the coaches are awesome and I value the great balance between academics and athletics."