The 33-year-old's contract has been resolved and he is free to look for a new club.
Nolan captained the east London club to promotion to the Premier League in 2012 and was their top scorer in the following two seasons. In all he scored 31 goals in 157 games for the club.
His departure was confirmed in a statement issued via the club's official website, www whufc.com.
It said: "West Ham United would like to thank Kevin for his considerable effort and commitment over the past four seasons and wish him all the very best for the future, on and off the football pitch."
Nolan, who joined the Hammers from Newcastle in June 2011, made public his feeling for the Toon owner.
Something Ashley has not forgiven him for.
Ashley was willing to take offers for him and he made it known the former Bolton skipper would never play for the Magpies again.
He said: "I've thoroughly enjoyed my time at West Ham United and will take some great memories with me. I'm now looking forward to the next challenge playing for a new club."
Nolan was signed by then new manager Sam Allardyce and appointed as skipper with the pair leading the relegated club back into the Barclays Premier league via the play-offs at the first attempt.
He contributed 13 goals to that successful campaign and demonstrated his enduring potency back in the top flight, where he found the back of the net 10 times in 35 appearances on his return.
However, Allardyce's departure at the end of the last campaign and the subsequent arrival of Slaven Bilic saw Nolan slip down the pecking order and, although he was involved in the Europa League qualifying campaign, he has started only one of the three Premier League games they have played to date this season, Saturday's 4-3 home defeat by promoted Bournemouth in which he was withdrawn at half-time.
Speaking at his pre-match press conference on Thursday morning, Bilic said of Nolan: "I can only say a big thanks to Kevin from the club because he was a great captain and a great professional. I wish him well."
THE TOON'S GREATEST 100 PLAYERS ... EVER!
AMAZON: http://www.amazon.co.uk/The-Toons-Greatest-Players-EVER/dp/132629685X
This book is a collection of the 100 Greatest Newcastle United players of all time, as voted for by NewcastleUtd-Mad.co.uk readers and a panel of journalists who contribute to the website. The players are in an order of five-per-chapter, counting down from 100 to Newcastle United's greatest ever player (as viewed by the author), but the whole point of the book is for YOU (the reader) to decide who goes where. The list is not, by any means, definitive. As with all books of this nature, whether it be "Greatest Albums"; "Best Movies Of All Time"; or "Top 100 Pin-Ups Of The Year" ... no two people have exactly the same opinion. There will be controversy over who is on the list, and chances are, more controversy over who is not. Here are the best of the best. I have painted the picture with each player's profile. Where they end up in the league of NUFC's Greatest is up to you. Because YOU have the final word.
Otherwise ... if you want a signed copy (for a birthday, etc) for £9.95 and no postage ... you can meet me before a match and I will bring a copy along.
Get in touch: Kevnumad@fsmail.net
NEWCASTLE UTD 4 NORTHAMPTON TOWN 1
Darlow, Janmaat, Lascelles, Williamson, Haidara (78' Toney), Tiote, Gouffran, Aarons, de Jong, Thauvin (65' Mitrovic), Perez (72' Colback).
Subs: Dummett, Wijnaldum, Mbemba, Elliot.
Florian Thauvin announced himself on Tyneside in style as he put League Two Northampton to the sword to book Newcastle's place in the third round of the Capital One Cup.
The £13million winger opened the scoring on his first start for the club, and then provided the ammunition for Siem De Jong, Daryl Janmaat and Mike Williamson to secure a 4-1 victory at St James' Park with Marc Richards' 10th-minute penalty having briefly given the League Two side hope.
It was a first win of the season for new manager Steve McClaren, and while there are sterner tests to come, Thauvin's contribution and those of De Jong and Ayoze Perez in particular in front of a delighted crowd of 26,923 will have provided encouragement.
Newcastle have publicly reversed their recent domestic cup policy this season and McClaren insisted in the run-up to the game that he would field his "strongest team possible", although in the event, he made nine changes to the side which drew 0-0 at Manchester United on Saturday.
That included Thauvin's full debut and yet another return from injury for luckless midfielder De Jong, who was handed the captain's armband, and the pair were to make almost immediate impacts.
The game was less than three minutes old when the Frenchman stretched out a leg at the far post to turn home Massadio Haidara's cross, and just five more minutes had elapsed when De Jong rose to glance Thauvin's inswinging free-kick past goalkeeper Ryan Clarke.
However, the visitors were quite literally handed a lifeline when Rod McDonald's header from Adam Yates' free-kick struck Cheick Tiote's arm and referee David Coote pointed straight to the spot to hand Cobblers skipper Richards the chance to level, and he did not pass it up.
Richards headed just wide at the near-post seven minutes later with Town taking advantage of Newcastle's carelessness, although the Premier League outfit might have wrapped up victory by half-time with Clarke saving twice from Perez and blocking an injury-time effort from De Jong, who had earlier headed wide from close range.
Yoan Gouffran whipped a shot into the side-netting from Perez's 49th-minute lay-off as the Magpies attempted to kill the tie off, and they extended their lead with 56 minutes gone when Perez, De Jong and Thauvin combined before full-back Janmaat ran on to the Frenchman's beautiful reverse pass to beat the keeper.
The contest was effectively over seven minutes later when Williamson converted another Thauvin free-kick with an unopposed header, and McClaren withdrew the former Marseille winger to warm applause as Aleksandar Mitrovic joined the fray.
Chris Wilder's men, who had fought gamely throughout, continued to do so all the way to the whistle, but to no avail.
NEWCASTLE UNITED
Fri 10th July (8pm BST)
Gateshead FC 0 Newcastle Utd 1 (Cisse pen)
(First half): Darlow, Janmaat, Haidara, Lascelles, Williamson, Anita, Colback, Gouffran, Cisse, Sissoko, De Jong. (Second half): Woodman, Bigirimana, Satka, Good, Ferguson, Tiote, Obertan, Aarons, Perez, Armstrong, Riviere.
Tue 14th July (8pm CT)
Club Atlas (MEX) 2 Newcastle Utd 1 (Sissoko)
Krul (Darlow 46); Janmaat (Bigirimana 72), Williamson, Lascelles, Haidara (Ferguson 72); Anita, Colback; Sissoko (Obertan 72), de Jong (Perez 72), Gouffran (Aarons 72); Cisse (Armstrong 72).
Sat 18th July (8pm UTC)
Sacramento Republic FC (USA) 0 Newcastle Utd 1 (og)
Krul (Woodman 46), Janmaat, Williamson, Lascelles (Taylor 46), Haïdara, Anita, Colback, Sissoko, Obertan (Aarons 69), de Jong (Perez 69), Cissé (Wijnaldum 69).
Tue 21st July (7.30pm UTC)
Portland Timbers (USA) 4 Newcastle Utd 3 (Wijnaldum, Aarons 2)
Darlow (Woodman 46), Bigirimana, Satka, Ferguson, Aarons; Abeid (Anita 65), Wijnaldum (Janmaat 46), Gouffran (De Jong 76), Sissoko (Obertan 46), Ayoze, Cisse (Armstrong 46).
Sun 26th July (1pm BST)
Sheffield United 2 Newcastle Utd 2 (Wijnaldum, de Jong)
Krul, Janmaat, Williamson, Taylor (Lascelles 69), Haïdara, Anita (Obertan 59), Colback, Sissoko (Abeid 80), Wijnaldum (De Jong 73), Perez (Aarons 45), Cissé (Armstrong 80)
Wed 29th July (7.45pm BST)
York City 2 Newcastle Utd 1 (Perez)
Darlow (Elliot HT); Bigirimana, Lascelles, Satka, Ferguson; Abeid, Gouffran; Aarons (Kemen 59), De Jong, Perez; Mitrovic (Suddick 70)
Sat 1st August (3pm BST)
Newcastle Utd 0 Borussia Mönchengladbach 1
Krul, Janmaat (Mbemba 62), Williamson, Taylor, Haïdara, Anita (De Jong 75), Colback, Sissoko (Perez 81), Obertan (Aarons 62), Wijnaldum, Cissé (Mitrovic 62).
Sunday August 9
NEWCASTLE UTD 2 SOUTHAMPTON 2 (Cisse, Wijnaldum)
Krul, Janmaat, Mbemba, Coloccini, Haidara; Colback, Anita (Tiote, 67); Sissoko, Wijnaldum (De Jong, 81), Obertan; Cisse (Mitrovic, 75). Subs not used: Darlow, Taylor, Aarons, Perez.
Saturday August 15
SWANSEA CITY 2 NEWCASTLE UTD 0
Krul, Janmaat, Mbemba, Coloccini, Haidara, Anita, Colback, Sissoko (45' Taylor), Wijnaldum, Obertan (82' Mitrovic), Cisse (54' Aarons). Subs: Williamson, Perez, Tiote, Darlow
Saturday August 22
MANCHESTER UTD 0 NEWCASTLE UTD 0
Krul, Mbemba, Taylor, Coloccini, Haidara, Anita, Colback, Perez (78' Tiote), Wijnaldum, Obertan (69' Thauvin), Mitrovic (88' Cisse).
Subs: Williamson, de Jong, Aarons, Darlow
Tuesday August 26
NEWCASTLE UTD 4 NORTHAMPTON TOWN 1 (Thauvin, Janmaat, de Jong, Williamson
Darlow, Janmaat, Lascelles, Williamson, Haidara (78' Toney), Tiote, Gouffran, Aarons, de Jong, Thauvin (65' Mitrovic), Perez (72' Colback).
Subs: Dummett, Wijnaldum, Mbemba, Elliot.
Saturday August 29
NEWCASTLE UTD 0 ARSENAL 1
Krul, Janmaat, Mbemba, Coloccini, Haidara, Anita (72' Perez), Sissoko (78' Cisse), Wijnaldum, Thauvin (87' de Jong), Mitrovic
Subs: Obertan, Tiote, Darlow, Taylor
Monday September 14
20:00 West Ham United v Newcastle United
Saturday September 19
15:00 Newcastle United v Watford
Wednesday September 23
19:45 Newcastle United v Sheffield Wednesday (League Cup)
Saturday September 26
17:30 Newcastle United v Chelsea