He previously played for Veendam, Heerenveen, Plymouth Argyle, Blackpool, Sheffield United, Charlton Athletic, Bradford City, VVV Venlo, Central Coast Mariners and FC Emmen.
Born in Winschoten, Seip made his debut for Eerste Divisie side BV Veendam in 1999, making six appearances in the 1999–2000 season.
Seip played in all five of the club's games in the Intertoto Cup, as they reached the finals, where they lost to Spanish La Liga side Villarreal.
After a trial with Russian side Spartak Moscow, Seip moved to England on 7 September 2006 with Championship club Plymouth Argyle, initially on a three-month contract.
After a 1–3 defeat at home to Sheffield Wednesday on 29 August 2009, Seip was again placed on the transfer list after a "breach of discipline", reported to have been a "dressing room bust up with manager Paul Sturrock".
After receiving clearance to play, three days later he made his first team debut, and scored the opening goal in a 2–0 win over his parent club, Plymouth Argyle, at Bloomfield Road.
He was named in The Championship "Team of the Week", along with teammates Stephen Crainey and Matthew Gilks, following his performance in Blackpool's 0–0 draw with Swansea City on 24 October at the Liberty Stadium.
[14] His time at Bramall Lane was interrupted by injuries however, and he made only eight appearances for the South Yorkshire club before his loan spell expired.
[18][19] Shortly scoring his first goal for the club, Seip signed a new deal with Bradford City, keeping him until the end of the season.
[25] He made his Mariners debut as a substitute in the first round of the 2013–14 A-League, coming on with ten minutes remaining in a draw with Western Sydney Wanderers.
[27] Seip left Central Coast Mariners after the end of the 2013/14 A-League season, well short of his initial 3-year deal due to a change of ownership at the club nullifying all player contracts, and not being offered a continuation of the original term.
[28] Seip married his longtime girlfriend Lucy, daughter of former Plymouth Argyle chairman Paul Stapleton, on 13 June 2009 in Gunnislake.