趙桓(宋(song)(song)欽宗(zong)(zong))即位后(hou),升李(li)(li)(li)綱(gang)(gang)(gang)(gang)為(wei)尚書右丞,就任(ren)親征行(xing)(xing)營使(shi)(shi),負責開(kai)(kai)(kai)(kai)封(feng)(feng)(feng)的(de)防(fang)御。李(li)(li)(li)綱(gang)(gang)(gang)(gang)率領開(kai)(kai)(kai)(kai)封(feng)(feng)(feng)軍(jun)(jun)(jun)民(min)及時(shi)完成防(fang)御部署,親自(zi)登城督戰,擊退金(jin)(jin)兵(bing)。金(jin)(jin)帥完顏(yan)宗(zong)(zong)望見開(kai)(kai)(kai)(kai)封(feng)(feng)(feng)難以(yi)強攻(gong)(gong),轉而施行(xing)(xing)誘(you)降(jiang)(jiang)之(zhi)(zhi)計,宋(song)(song)廷(ting)彌漫了(le)屈(qu)辱(ru)投降(jiang)(jiang)的(de)氣氛。李(li)(li)(li)綱(gang)(gang)(gang)(gang)因(yin)堅決反對向金(jin)(jin)割地求(qiu)和,被(bei)(bei)(bei)宋(song)(song)欽宗(zong)(zong)罷(ba)官(guan)。由于(yu)開(kai)(kai)(kai)(kai)封(feng)(feng)(feng)軍(jun)(jun)(jun)民(min)憤怒示威,迫(po)(po)使(shi)(shi)宋(song)(song)欽宗(zong)(zong)收回成命,李(li)(li)(li)綱(gang)(gang)(gang)(gang)才又(you)(you)(you)被(bei)(bei)(bei)起用(yong)。完顏(yan)宗(zong)(zong)望因(yin)無(wu)力攻(gong)(gong)破開(kai)(kai)(kai)(kai)封(feng)(feng)(feng),在(zai)宋(song)(song)廷(ting)答(da)應割讓河(he)北(bei)三鎮之(zhi)(zhi)后(hou),遂(sui)于(yu)靖康元(yuan)年(nian)(nian)(1126年(nian)(nian))二月(yue)(yue)撤(che)兵(bing)。開(kai)(kai)(kai)(kai)封(feng)(feng)(feng)守衛戰在(zai)李(li)(li)(li)綱(gang)(gang)(gang)(gang)組織下(xia)(xia)(xia)獲得勝利(li)。金(jin)(jin)兵(bing)撤(che)離之(zhi)(zhi)后(hou),李(li)(li)(li)綱(gang)(gang)(gang)(gang)即遭到宋(song)(song)廷(ting)投降(jiang)(jiang)派的(de)排斥和誣(wu)陷。靖康元(yuan)年(nian)(nian)(1126年(nian)(nian))五月(yue)(yue),宋(song)(song)廷(ting)強令李(li)(li)(li)綱(gang)(gang)(gang)(gang)出任(ren)河(he)東、河(he)北(bei)宣撫使(shi)(shi),驅趕他(ta)出朝。李(li)(li)(li)綱(gang)(gang)(gang)(gang)就任(ren)后(hou),宋(song)(song)廷(ting)又(you)(you)(you)事事加(jia)以(yi)限制(zhi),使(shi)(shi)宣撫使(shi)(shi)徒具空名(ming),無(wu)節(jie)制(zhi)軍(jun)(jun)(jun)隊之(zhi)(zhi)權。李(li)(li)(li)綱(gang)(gang)(gang)(gang)被(bei)(bei)(bei)迫(po)(po)于(yu)靖康元(yuan)年(nian)(nian)(1126年(nian)(nian))九月(yue)(yue)辭職(zhi),旋又(you)(you)(you)被(bei)(bei)(bei)加(jia)上(shang)“專主戰議,喪師費(fei)財(cai)”的(de)罪(zui)名(ming),先(xian)責建昌軍(jun)(jun)(jun)(今江西南城)安置,再(zai)謫夔州(今重慶(qing)奉節(jie)白(bai)帝城)。李(li)(li)(li)綱(gang)(gang)(gang)(gang)被(bei)(bei)(bei)貶不(bu)久,金(jin)(jin)兵(bing)再(zai)次(ci)兩路(lu)南下(xia)(xia)(xia)圍(wei)攻(gong)(gong)開(kai)(kai)(kai)(kai)封(feng)(feng)(feng)。宋(song)(song)欽宗(zong)(zong)在(zai)被(bei)(bei)(bei)俘前夕又(you)(you)(you)想起用(yong)李(li)(li)(li)綱(gang)(gang)(gang)(gang),任(ren)命他(ta)為(wei)資政殿大(da)學士、領開(kai)(kai)(kai)(kai)封(feng)(feng)(feng)府事,但已無(wu)濟于(yu)事。南宋(song)(song)建立后(hou),他(ta)主張堅決抗金(jin)(jin)及反對投降(jiang)(jiang)活(huo)動,卻為(wei)宋(song)(song)高宗(zong)(zong)及汪伯彥、黃潛善(shan)所(suo)不(bu)容。因(yin)此(ci),他(ta)們又(you)(you)(you)設法(fa)驅逐李(li)(li)(li)綱(gang)(gang)(gang)(gang)。首先(xian),調李(li)(li)(li)綱(gang)(gang)(gang)(gang)任(ren)尚書左(zuo)仆(pu)射(she)兼門(men)下(xia)(xia)(xia)侍(shi)郎(lang)(左(zuo)相(xiang)),另委(wei)黃潛善(shan)接(jie)任(ren)右仆(pu)射(she)兼中書侍(shi)郎(lang),以(yi)牽制(zhi)李(li)(li)(li)綱(gang)(gang)(gang)(gang)。接(jie)著,又(you)(you)(you)罷(ba)免張所(suo)、傅亮,撤(che)銷河(he)北(bei)招撫司(si)及河(he)東經制(zhi)司(si),蓄(xu)意破壞李(li)(li)(li)綱(gang)(gang)(gang)(gang)的(de)抗金(jin)(jin)部署,迫(po)(po)使(shi)(shi)李(li)(li)(li)綱(gang)(gang)(gang)(gang)辭職(zhi)。李(li)(li)(li)綱(gang)(gang)(gang)(gang)主政僅七(qi)十五天,建炎(yan)元(yuan)年(nian)(nian)(1127年(nian)(nian))八(ba)月(yue)(yue)十八(ba)日便遭罷(ba)相(xiang),為(wei)觀文殿大(da)學士,提舉杭州洞霄宮。一生為(wei)國,卻不(bu)得愿。