趙(zhao)桓(宋(song)(song)欽(qin)宗(zong)(zong))即(ji)位后,升李(li)(li)(li)(li)(li)(li)綱(gang)(gang)(gang)為(wei)尚書右(you)丞,就(jiu)任(ren)(ren)親(qin)征行營使(shi)(shi),負責開(kai)(kai)(kai)封(feng)(feng)(feng)的防(fang)御。李(li)(li)(li)(li)(li)(li)綱(gang)(gang)(gang)率領(ling)(ling)開(kai)(kai)(kai)封(feng)(feng)(feng)軍民及時完成防(fang)御部(bu)署(shu),親(qin)自登(deng)城督戰,擊退金(jin)兵(bing)。金(jin)帥完顏(yan)宗(zong)(zong)望(wang)見開(kai)(kai)(kai)封(feng)(feng)(feng)難以強攻,轉而施行誘降(jiang)之計,宋(song)(song)廷(ting)(ting)彌漫了屈辱投(tou)(tou)降(jiang)的氣氛。李(li)(li)(li)(li)(li)(li)綱(gang)(gang)(gang)因堅(jian)決(jue)反(fan)對向(xiang)金(jin)割地求和,被(bei)(bei)宋(song)(song)欽(qin)宗(zong)(zong)罷官。由于(yu)(yu)(yu)開(kai)(kai)(kai)封(feng)(feng)(feng)軍民憤怒示(shi)威,迫使(shi)(shi)宋(song)(song)欽(qin)宗(zong)(zong)收回成命,李(li)(li)(li)(li)(li)(li)綱(gang)(gang)(gang)才(cai)又(you)(you)被(bei)(bei)起用(yong)。完顏(yan)宗(zong)(zong)望(wang)因無(wu)力攻破開(kai)(kai)(kai)封(feng)(feng)(feng),在(zai)宋(song)(song)廷(ting)(ting)答應割讓河北(bei)三鎮之后,遂于(yu)(yu)(yu)靖康元(yuan)年(nian)(1126年(nian))二月撤兵(bing)。開(kai)(kai)(kai)封(feng)(feng)(feng)守(shou)衛(wei)戰在(zai)李(li)(li)(li)(li)(li)(li)綱(gang)(gang)(gang)組織下(xia)獲(huo)得勝利(li)。金(jin)兵(bing)撤離(li)之后,李(li)(li)(li)(li)(li)(li)綱(gang)(gang)(gang)即(ji)遭到宋(song)(song)廷(ting)(ting)投(tou)(tou)降(jiang)派的排(pai)斥和誣陷。靖康元(yuan)年(nian)(1126年(nian))五(wu)月,宋(song)(song)廷(ting)(ting)強令(ling)李(li)(li)(li)(li)(li)(li)綱(gang)(gang)(gang)出(chu)(chu)任(ren)(ren)河東、河北(bei)宣(xuan)撫(fu)使(shi)(shi),驅趕(gan)他(ta)出(chu)(chu)朝。李(li)(li)(li)(li)(li)(li)綱(gang)(gang)(gang)就(jiu)任(ren)(ren)后,宋(song)(song)廷(ting)(ting)又(you)(you)事(shi)事(shi)加(jia)(jia)以限制(zhi),使(shi)(shi)宣(xuan)撫(fu)使(shi)(shi)徒具空名(ming),無(wu)節制(zhi)軍隊之權。李(li)(li)(li)(li)(li)(li)綱(gang)(gang)(gang)被(bei)(bei)迫于(yu)(yu)(yu)靖康元(yuan)年(nian)(1126年(nian))九(jiu)月辭職(zhi),旋(xuan)又(you)(you)被(bei)(bei)加(jia)(jia)上(shang)“專主(zhu)戰議,喪師費財”的罪名(ming),先責建昌軍(今(jin)江(jiang)西(xi)南城)安置,再(zai)謫夔(kui)州(今(jin)重慶奉節白(bai)帝城)。李(li)(li)(li)(li)(li)(li)綱(gang)(gang)(gang)被(bei)(bei)貶不久,金(jin)兵(bing)再(zai)次兩路(lu)南下(xia)圍攻開(kai)(kai)(kai)封(feng)(feng)(feng)。宋(song)(song)欽(qin)宗(zong)(zong)在(zai)被(bei)(bei)俘前夕又(you)(you)想起用(yong)李(li)(li)(li)(li)(li)(li)綱(gang)(gang)(gang),任(ren)(ren)命他(ta)為(wei)資政殿大學士、領(ling)(ling)開(kai)(kai)(kai)封(feng)(feng)(feng)府事(shi),但已無(wu)濟(ji)于(yu)(yu)(yu)事(shi)。南宋(song)(song)建立后,他(ta)主(zhu)張堅(jian)決(jue)抗(kang)金(jin)及反(fan)對投(tou)(tou)降(jiang)活動,卻(que)為(wei)宋(song)(song)高(gao)宗(zong)(zong)及汪伯彥、黃潛(qian)善(shan)所不容。因此,他(ta)們又(you)(you)設法(fa)驅逐(zhu)李(li)(li)(li)(li)(li)(li)綱(gang)(gang)(gang)。首先,調(diao)李(li)(li)(li)(li)(li)(li)綱(gang)(gang)(gang)任(ren)(ren)尚書左(zuo)仆射兼門下(xia)侍(shi)郎(lang)(lang)(左(zuo)相(xiang)),另委黃潛(qian)善(shan)接任(ren)(ren)右(you)仆射兼中書侍(shi)郎(lang)(lang),以牽(qian)制(zhi)李(li)(li)(li)(li)(li)(li)綱(gang)(gang)(gang)。接著,又(you)(you)罷免(mian)張所、傅(fu)亮,撤銷河北(bei)招撫(fu)司(si)及河東經制(zhi)司(si),蓄意破壞李(li)(li)(li)(li)(li)(li)綱(gang)(gang)(gang)的抗(kang)金(jin)部(bu)署(shu),迫使(shi)(shi)李(li)(li)(li)(li)(li)(li)綱(gang)(gang)(gang)辭職(zhi)。李(li)(li)(li)(li)(li)(li)綱(gang)(gang)(gang)主(zhu)政僅七十五(wu)天,建炎元(yuan)年(nian)(1127年(nian))八月十八日(ri)便遭罷相(xiang),為(wei)觀文(wen)殿大學士,提舉杭州洞霄宮。一生為(wei)國,卻(que)不得愿(yuan)。