|Full name||William Osael Romero Castillo|
|Date of birth||18 April 1986|
|Place of birth||Usulután, El Salvador|
|Height||1.68 m (5 ft 6 in)|
|Playing position||Midfielder/Attacking midfielder|
|2010||→ Chivas USA (loan)||9||(1)|
|2004–2005||El Salvador U-20|
* Senior club appearances and goals counted for the domestic league only and correct as of 1 March 2014|
‡ National team caps and goals correct as of 7 September 2012
On 1 February 2010, Chivas USA signed El Salvador international from FC Dallas who held a discovery claim on the player, the 23-year-old midfielder arrived in Los Angeles and comes on loan from Vista Hermosa. On 26 June 2010, Romero scored his first MLS goal with Chivas USA in a game against FC Dallas at The Home Depot Center, in which ended 1–2 in favor of FC Dallas.
He returned to his home country to join Águila for the 2010 Apertura.
Romero officially received his first cap on 13 October 2007 in a friendly match against Costa Rica. He scored his first goal for the national team on 22 October 2008 in a friendly match against Bolivia. Arguably, Romero's greatest moment to date as a Salvadoran international came on 11 February 2009 in a World Cup qualification match against Trinidad and Tobago when he scored two late goals from free kicks in the dying moments of the game to even the scores and save El Salvador from a disappointing home loss. The game ended at 2–2. During the 2009 Gold Cup, Romero scored two goals against Costa Rica that gave El Salvador a victory over traditional rivals Costa Rica.
As of February 2012, he has represented his country in 19 FIFA World Cup qualification matches and played at the 2009 and 2011 UNCAF Nations Cups as well as at the 2009 and 2011 CONCACAF Gold Cups.
On 20 September 2013, Romero was one of 14 Salvadoran players banned for life due to their involvement with match fixing.
|Atlético Chaparratique||El Salvador El Salvador||2006|
|Vista Hermosa||El Salvador El Salvador||2006–2010|
|Chivas USA (cedido)||United States USA||2010|
|Águila||El Salvador El Salvador||2011–2012|
|Alianza||El Salvador El Salvador||2013–present|
|Salvadoran Primera División||C.D. Vista Hermosa||2005|
|Top Scorer Salvadoran Primera División FESFUT (15 goles)||2009|
|Player of the Year Salvadoran Primera División FESFUT||2006–2010|
- Osael Romero signs with Chivas USA – Los Angeles Times
- Gracias, Osael – La Prensa Grafica (in Spanish)
- El Salvador stuns Costa Rica 2–1 with late goal – Gold Cup 2009
- Osael Romero – FIFA competition record
- UNCAF (Qualifying Tournament for Gold Cup) 2009 – Details – RSSSF
- Copa Centroamericana 2011 (UNCAF Nations Cup) – RSSSF
- CONCACAF Championship, Gold Cup 2009 – Full Details – RSSSF
- CONCACAF Championship, Gold Cup 2011 – Full Details – RSSSF
- "El Salvador match-fixing: 14 footballers banned for life". BBC. Retrieved 21 September 2013.