Born in Southport, Merseyside, Cowan attended the LTA Rover School at Bisham Abbey. He was also a member of Aughton Tennis Club. A left-hander, Cowan was a versatile sportsman in his junior years; aside from tennis, Barry represented the North of England at under-15 level hockey and is also a member of OrmskirkGolf Club. After success in junior tournaments, Cowan first competed at the All England Club in 1994 as a wild card, losing in the first round to that year's French Open champion Sergi Bruguera in four sets.
2000
Cowan was only to appear regularly in Grand Slams as a Wimbledon wild card. However he was successful in qualifying for the U.S. Open at Flushing Meadows in 2000, though he lost in straight sets to Jens Knippschild. Cowan later represented Britain at the Sydney Olympics taking the first set but eventually losing to Daniel Nestor in round one.
Match with Pete Sampras, Wimbledon 2001
In 2001, Cowan once again gained a wild card entry into Wimbledon, and won his first ever SW19 singles match in a battle of Britain against Mark Hilton in straight sets, setting up a dream second round match against Sampras, undefeated at Wimbledon since 1996, the match was the epitome of a David & Goliath, with there being 264 places between the two in the World Rankings. As expected Sampras dominated the first two sets on Court 1, leading 6–3, 6–2 before Cowan came back against all expectations, taking an epic third set tie break. During breaks in play, Cowan would listen to music, notably You'll Never Walk Alone, which can be heard at Anfield home of his team Liverpool FC. Before the match he had sought advice from a top sports psychologist to help prepare himself for the daunting task of facing the world number one. The help seemed to pay off and with the partisan British crowd cheering Cowan on, Cowan upset the form book to break the Sampras serve to win the fourth set 6–4 and take it into a final set. However, all dreams of an upset evaporated as Sampras broke back in the final set to win 6–3, 6–2, 6–7, 4–6, 6–3.
In September 2001, Cowan played in his only Davis Cup singles match representing Britain in a World Group Qualifier against Ecuador, he lost in straight sets to Luis Adrijan Moreon 6–1, 6–4, although the result did not affect Britain's performance, as they beat Ecuador 4–1 overall.
2002 and retirement
Cowan would once again reach the second round at Wimbledon a year later, bowing out in four sets to Ecuador's Nicolás Lapentti. After that defeat, Cowan announced his retirement from professional tennis.
After retirement
Since retiring from the game, Cowan has taken up a commentating role with Sky Sports for their tennis coverage. Outside the game, Cowan is a keen supporter of Liverpool Football Club.
