2017-18: Put in a career-best time of 1:41.85 in the 200 free at the Big Ten Championships ... Swam a 1:42.02 200 free and finished 14th at the TYR Invitational (11/17-19) ... Also took 11th in the 1650 free and 12th in the 500 free with a season-best 4:36.13 at TYR ... Came in third in the 500 and 1000 free against Eastern Michigan (10.11) ... Swam a season-best 9:49.04 1000 free against Iowa (1.20) to come in fifth.2016-17: Ranked third on NU's top times list in the 1,000 free and the 1,650 free ... Finished 36th at the Big Ten Championships in the 1,650 free ... Finished fourth against Iowa in the 1000 free ... Finished fourth in tri-dual meet against Duke and NC State in 1000 free ... Finished 6th in 1,650 free at TYR ... Academic All-Big Ten.
2015-16: Ranked second on NU’s top times list in the 1,000 free and 1,650 free, and third in the 500 free…Member of the 800 free relay team…Set a personal best time of 9:37.15 at Missouri quad-duel in 1,000 free…Took second in 1,000 free and 500 free at UIC quad-dual…Finished third in 1,000 free and fourth in 500 free for a total of 5 points against Wisconsin…Made the consolation final in the 500 free at the TYR Invitational to finish ninth…Finished fifth in the 1,650 free at TYR for 14 points.
2014-15: Freshman member of Northwestern's distance freestyle group … Ranked third on NU's top times list in the 1,000 free and 1,650 free, and fourth in the 500 free following the season … Swam career-best times in all three of his events at the Big Ten Championships … Swam the 1,650 free over 30 seconds faster to place 24th in the conference in 15:35.60 … In the 500 free, cut a full 8.0 seconds from his previous best to finish 40th in 4:30.54 … Dropped 2.08 seconds in the 200 free to place 50th at the B1G meet … Finished ninth in the 1,650 at the Wildcats' home TYR Invitational (11/21-11/23) to score points for NU … Won the bonus final of the 500 free at the TYR with a 4:38.54 that represented a 5.62 second drop from his preliminary time in the race … Also had a TYR second swim in the 100 back, placing 21st … Scored dual meet points for NU five times during the year, all in the 1,000 free event … Best finish in the race was a second-place effort in a double dual sweep of UIC and Oakland (10/25) … Competed at AT&T U.S. Winter Nationals to conclude the fall, swimming in the 1,650 free, 500 free and 200 free.
High School: Ranked as the No. 6 swimmer in Connecticut by Collegeswimming.com ... All American and All state during the 2013-14 year ... Lettered in swimming for two season 2011-12 ... FCIAC CO-MVP 2013 ... Norwalk Hour All-Area MVP 2013-14, and Norwalk Hour All-Area team 2012-14 ... Connecticut Post All-Star 2013-14 ... Team Achievements include FCIAC Record Holder 500 free ... Record holder in the 100 free, 200 free, 400 free, and 500 free ... Also competed with club team from 2003-2014 ... Won second place in the YMCA sort course championships 2014, fifth place for 500 free 2013 ... Connecticut Senior long course champion 1500 free and 800 free 2013 ... Connecticut distance High Point winner 2012 ... Club team record holder 400, 500,1 000 free ... Junior National qualifier 2013-2014.
Personal: Born Jonathan Rock Blansfield ... Son of Lourdes and David Blansfield ... Chose Northwestern over Indiana ... Major is Communication Studies.
BLANSFIELD'S PERSONAL BESTS
| Event | Personal Best |
| 200 freestyle | 1:41.85 |
| 500 freestyle | 4:30.54 |
| 1,000 freestyle | 9:37.15 |
| 1,650 freestyle | 15:35.60 |
| 200 backstroke | 1:51.48 |