[5] Born in Willemstad, Netherlands Antilles,[6] Agustien began his career in the youth system of Dutch club Willem II.

Birmingham manager Alex McLeish "couldn't commit [himself] to bringing him in for the money asked", so Agustien returned to AZ when his contract expired on 26 May 2009.

[19] By February 2011, Agustien was anxious for regular first-team football, and suggested that there had been interest from clubs in taking him on loan, but manager Brendan Rodgers considered him part of the Swansea squad.

[22] He made his Premier League debut for the newly promoted Swansea in a 4–0 loss against Manchester City,[23] but suffered a hamstring injury in September, and was restricted to one brief substitute appearance in the next three months.

[29] Ahead of the 2013–14 season, Agustien, along with Alan Tate, Luke Moore and Leroy Lita, was left out of the squad for the pre-season tour, which led their future uncertain.

[30] During July 2013, Agustien transferred to Championship club Brighton & Hove Albion signing a two-year contract,[31] however the deal was delayed for a number of days whilst awaiting international clearance which was finally completed on 1 August.

[37] On 25 September 2015, it was announced that Agustien had signed a contract with the Danish 1st Division side Vendsyssel FF until the end of the year.

[41] Agustien returned to Dutch football for 2016–17, signing a one-year contract with Eerste Divisie club FC Dordrecht.

[44] Agustien signed for English National League North club Nuneaton Borough on 27 June 2018,[45] but left again by mutual consent before the season started.

[35][52] He signed for Bradford (Park Avenue) of the National League North in late September 2019, and went straight into the starting eleven for their visit to Brackley Town.

[60] At international level, he was a member of the Netherlands under-20 squad for the 2005 FIFA World Youth Championship, where he played in two of the group-stage matches.

[67] In 2014, Agustien decided to represent his country of birth, receiving his first call-up for the Curaçao senior team ahead of the 2014 Caribbean Cup in Jamaica.