Dowlen won the USTA National Boys 18 Championship in 1978. After, he was a leading player on the University of Houston tennis team.
Dowlen enjoyed most of his tennis success while playing doubles. During his career, he won four doubles titles. He achieved a career-high doubles ranking of World No. 30 in 1984. He achieved much of his success alongside doubles partner Nduka Odizor, including beating John McEnroe.
|Win||1.||1983||Monterrey, Mexico||Carpet||Nduka Odizor|| Andy Andrews
|3-6, 6-3, 6-4|
|Loss||1.||1984||Boca West, U.S.||Hard||Nduka Odizor|| Mark Edmondson
|6-4, 1-6, 4-6|
|Loss||2.||1984||Houston, U.S.||Clay||Nduka Odizor|| Pat Cash
|5-7, 6-4, 3-6|
|Win||2.||1984||Forest Hills WCT, U.S.||Clay||Nduka Odizor|| Ernie Fernandez
|Win||3.||1984||Tokyo Outdoor, Japan||Hard||Nduka Odizor|| Mark Dickson
|6-7, 6-4, 6-3|
|Loss||3.||1985||Melbourne Indoor, Australia||Carpet||Nduka Odizor|| Brad Drewett
|6-4, 6-7, 4-6|
|Win||4.||1985||Sydney Outdoor, Australia||Grass||Nduka Odizor|| Broderick Dyke