雍正六年（1728）雍正帝为更新吏治，实行全国荐才，李方膺以“贤良方正”受到举荐。次年，李玉鋐到京城述职，三十四岁的李方膺随父进京。觐见时，雍正皇帝怜悯李玉鋐年老，问：有儿子和你一同来么？”对曰：“第四子方膺同来。”问：“何职，且胜官否？”对曰：“生员也，性赣，不宜官。”雍正笑曰：“未有学养子而后嫁者。”即召见，特旨交主管河南、山东的河东总督田文镜委派为沿海知县。
雍正八年（1730）李方膺任山东乐安知县。当年夏秋之际，乐安大水成灾，万家漂橹，情势紧迫。李方膺未得上司批准，开仓赈济，下令动用库存皇粮一千二百石，以工代赈，募民筑堤，缓解了灾情。但随即因私开官仓被青州府弹劾。总督田文镜未予置理，反而称赞李方膺胆识过人，有功于民。灾后，经实地考察，李方膺写下《小清河议》、《民瘼要览》、《山东水利管窥》等著作。雍正十年（1732）因功升任莒州知州。雍正十二年（1734）他奉调返任乐安知县，同年冬改任兰山知县。
雍正十三年（1735）他因反对新任总督王文俊的垦荒令，上书直陈弊端，触怒上司，被罢官入狱，成为当时震惊朝野的“兰山冤案”。民哗然曰：“公为民故获罪，请环流视狱”，兰山、莒州一带农民成群结队，自带鸡黍米酒前往青州监狱探视。狱吏不许见，老百姓就把带来的钱物、食品往监狱的高墙里扔，留下的酒坛子把监狱的大门和甬道都堵住了。这场冤狱，一拖三年。直到清乾隆元年（1736），乾隆追究起开垦失策忧民之事，罢王士俊，才得平反。那天二鼓，文书传到青州，当夜李方膺就被释放。 李方膺入都觐见，立候在军机房丹墀西槐树下，大学士朱轼指给诸王大臣说：这就是劝阻开垦的知县李兰山也。那些欲见而挤不上前的人，以手加额远望着说：就是那个瘦而长，眼睛很有神的那位吗？少宗伯赵国麟和李方膺的父亲是同年进士，握着李方膺的手说：“李贡南有子矣” 。觐见后，调安徽以知县任用，李方膺请假回乡奉养老母而不就任。
乾隆四年（1739）后，李方膺父母相继去世，在家服丧六年。守制期满，受命任安徽潜山县令，权知滁州府，不久调任合肥县令。这时又逢饥荒，李方膺按过去做法，自订救灾措施，且不肯“孝敬”上司，遭嫉恨，太守加之莫须有的“贪赃枉法”罪名，罢官。前后做县令二十年，竟三次为太守所陷，李方膺感慨万千地说：两汉吏治，太守成之；后世吏治，太守坏之。
李方膺罢官后在南京寄居金陵（南京）项氏借园，自号借园主人，常往来扬州卖画以资衣食，他在晚年有诗说：“我是无田常乞米，梅园终日卖梅花”，画上也常钤“换米糊口”之印。与居住在南京的大诗人袁枚和篆刻家沈凤过从甚密，时常联袂出游，时人称之为“三仙出洞”。
在南京，李方膺还结识了篆刻家丁敬。丁敬傲岸不群，当时千金难得其一印，但李方膺却得到过丁敬刻赠的好几方印。有人觉得很奇怪，丁敬自己在《印跋》言明： 通州李方膺晴江，工画梅，傲岸不羁。罢官寓金陵项氏园，日与沈补萝、袁子才游……予爱其诗，为作数印寄之，聊赠一枝春意。
乾隆十九年（1754），在南京卖画五个年头的李方膺因身体不适回乡。病重时，曾勉力致书袁枚：“方膺归两日，病笃矣！今将出身本末及事状呈子才阁下。方膺生而无闻，借子之文光于幽宫可乎！九月二日拜白”。这是托袁枚为己写墓铭。待到袁枚收到这封绝笔，李方膺已离世多日了。据送信人说：此“此吾主死之前一日，命元扶起，力疾书也”。也即清乾隆甲戌（1754）的九月三日，这年他59岁，得的是“噎疾”（食道癌），医者曰：“此怀奇负气，郁而不舒之故，非药所能平也”。临终前，他在自己的棺木上写下一生的遗憾：“吾死不足惜，吾惜吾手！”
李方膺善画松、竹、兰、菊、梅、杂花及虫 鱼，也能人物、山水，尤精画梅。作品纵横豪放、墨气淋漓，粗头乱服，不拘绳墨，意在青藤、白阳、竹憨之间。画梅以瘦硬见称，老干新枝，欹侧蟠曲，著名的题画梅诗有“不逢摧折不离奇”之句。还喜欢画狂风中的松竹。工书，能诗，后人辑有《梅花楼诗草》，仅二十六首，多数散见于画上。传世画作为《风竹图》、《游鱼图》等等。

南通籍著名画家李方膺既不是扬州人，又未如黄慎，金农等久住扬州卖画，何以得置身于“扬州八怪”之列？关于这个问题，《中华文史论丛》1980年第三辑所刊管劲丞遗稿《李方膺叙传》已经作了考证，其要点为：一、人品、画品和其他七人（按指李鱓，汪士慎、高翔、金农、黄慎、郑燮、罗聘）相当；
二、通州于雍正元年（1723）前，还只是一个属于扬州府的散州，李方膺于康熙五十七年（1718）入学时，籍贯便是扬州府通州，所以他是广义的扬州人。李方膺跟“扬州八怪”之翘楚郑板桥的友谊，除从上面提到的几人共同创作的《花卉图》，《三友图》已可略见一斑外，更有可述者。
首先，板桥对李方膺的画艺极为佩服，评价极高。墨竹是郑板桥最拿手的绝技，但他《题李方膺墨竹册》仍认为李的墨竹“东坡，与可畏之”连画墨竹的圣手苏轼，文同都“畏之”，可见其评价之高。至于对李方膺最擅长的墨梅，则论述更具体，评价更高，郑板桥在李方膺逝世五年后所作的《题李方膺画梅长卷》中说：
兰竹画，人人所为，不得好。梅花、举世所不为，更不得好。惟俗己俗僧为之，每见其大段大炭撑拄吾目，真恶秽欲呕也。晴江李四哥独为于举世不为之时，以难见工，以口口矣。故其画梅，为天下先。日则凝视，夜则构思，身忘于衣，口忘于味，然后领梅之神、达梅之性，挹梅之韵，吐梅之情，梅亦俯首就范，入其剪裁刻划之中而不能出。夫所谓剪裁者，绝不剪裁，乃真剪裁也；所谓刻划者，绝不刻画，乃真刻画。宜止曲行，不人尽天，复有莫知其然而然者，问之晴江，亦不自知，亦不能告人也，愚来通州、得睹此卷，精神浚发，兴致淋漓。此卷新枝古干，夹杂飞舞，令人莫得寻其起落，吾欲坐卧其下，作十日功课而后去耳。乾隆二十五年五月十三日板桥郑燮漫题。
在这幅画上，他还题了一首四言诗：梅根啮啮，梅苔烨烨，几瓣冰魂，千秋古雪。
据郑板桥在同一时间所作《题黄慎画丁有煜象卷》（《板桥书画拓片集》，原件藏南通博物馆）的跋语“郝香山，晴江李公之侍人也，宝其主之笔墨如拱壁，而索题跋于板桥老人。”郑板桥在乾隆二十五（1760）初夏他六十八岁时曾第二次来通州，李方膺的侍人郝香山拿出他所访藏的主人的画，请郑板桥题辞。郑有感于他与李方膺原来的深厚情谊和郝香山对其主人的一片忠义，便欣然命笔，写了上引题跋和诗，郑板桥这次来通州，住在城北二十余里的秦灶， “寓保培基井谷园”（金榜《海曲拾遗》），并去游狼山，在他的集子中，留下了《游白狼山》七绝两首。
这篇题跋先批判俗工俗僧所画梅花之令人作呕；接着称赞李亏膺所画梅花“以难见工”，“为天下先”并具体叙述其画梅时以不剪裁为剪裁，不刻划为刻划，顺乎梅之天性，不见人工雕琢的艺术经验；最后表示对这幅梅画的“新枝古干，夹杂飞舞”十分倾倒，愿意“坐卧其下，做十日功课而后去”。这篇题跋写得如此具体深刻、充满感情，也反映了郑板桥跟李云膺结交已久，接触甚多，知之甚深，是他们深厚友谊的重要见证。
李方膺解任合肥知县后，在南京借寓项氏花园，题名借园，从此定居下来，直至二十年（1755）秋因病回通州，其间整整四年时间，常与当时文坛泰斗袁枚，画家沈凤过从，谈诗论画，关系十分密切。袁枚曾在给李方膺的赠诗中写道：“我爱李晴江，鲁国一男子。梅花虽倔强，恰在春风里。超越言锯屑，落落如直矢。偶逢不平鸣，手作磨刀水。两搏扶摇风，掉头归田矣。偶看白下山，借园来居此。大水照窗前，新花插屋底。君言我爱听，我言君亦喜。陈遵为客贫，羲之以乐死。人生得朋友，何必思乡里。”乾隆二十年乙亥初春，李方膺曾回通州一次，袁枚亦有诗相送。诗集卷十一收了《送李晴江还通州》三首，第一首有句云：“才送梅花雪满衣，画梅人又逐飞。一灯对酒春何淡，四海论交影更稀。”所写确为初春景象，并明点“春” 字。
李方膺喜画风竹。他的《潇湘风竹图》画一方丑石，几竿湘竹，竹梢弯曲，竹叶向一个方向飘动，显示出狂风大作的情景。画上小题诗：
画史从来不画风，我于难处夺天工。
请看尺幅潇湘竹，满耳丁东万玉空。
李方膺画风竹是有深刻寓意的，他在另一首题《风竹图》中写道：
波涛宦海几飘蓬，种竹关门学画工。
自笑一身浑是胆，挥毫依旧爱狂风。
《苍松怪石图题诗》
君不见，岁之寒，
何处求芳草。
又不见，松之乔，
青春复矫矫。
天地本无心，万物贵其真。
直干壮川岳，秀色无等伦。
饱经冰与霜，千年方未已。
拥护天阙高且坚，
迥干春风碧云里。
他当地方官三十年，遭受过几次沉重的打击。雍正八年（1730）他在乐安知县任上，因开仓赈灾来不及请示上司，而受到了弹劾雍正十年（1732）他在兰山知县任上，总督王士俊盲目地下令开荒，官员们乘机勒索乡民，他坚决抵制，竟被投进监狱，吃了一年冤枉官司，最后是乾隆十四年（1749）在合肥知县任上，因抵忤上司竟被安上“贪赃枉法”的罪名而罢官。凡此种种，就是他所说的“波涛宦海几飘蓬”。官场太黑暗了，他便弃官去学画竹，当了“画工”，他的性格依然未变，“自笑一身浑是胆”，蔑视传统，蔑视权威，爱画狂风，以此寄托自己与恶劣环境坚决斗争的不屈精神。丁有煜曾曰：“（李方膺）谢事以后，其画益肆，为官主力，并而用之于画，故画无忌惮，悉如其气。”李方膺的笔下，狂风固然是不屈精神的象征，但这仅是画家性格的一个方面，体现了他跟恶势力斗争的一面;他的性格的另一方面，即对下层人民的关怀和同情，则促使他笔下的风化为使万物欣欣向荣的春风，使劳苦大众得到温暖的和风。他在《题画梅》诗中写道：
挥笔落纸墨痕新，几点梅花最可人。
愿借天风吹得远，家家门巷尽成春。
实际上，李方膺爱梅，是爱梅的秉性，爱梅的品格，其实是自我人格的外射。“识者谓李公为自家写生，晴江微笑而已”。 “为自家写生”，一语道破李方膺画梅的心态和内蕴。其题《梅花卷》云： 予性爱梅，即无梅之可见而所见无非梅。日月星辰梅也，山河川岳亦梅也，硕德宏才梅也，歌童舞女亦梅也……知我者梅也，罪我者亦梅也。李方膺好友袁枚评价其梅称：“傲骨郁作梅树根，奇才散作梅树花，孤干长招天地风，香心不死冰霜下”。

Li Fangying (1695 ~ 1755), the Chinese Qing Dynasty poet and painter, the word Qiu Zhong, No. Qingjiang, alias Qiuchi, Yanyuan, white mountain people, Tongzhou (now Jiangsu Nantong) people. Jinling by garden, since the park by the owner. As "Yangzhou eight strange" one. Lushan county magistrate, hill county magistrate, deputy Chuzhou state magistrate and other staff, when the official, "there are benefits, morality", after being accused of being dismissed from office, after Quguan Apartments in Nanjing by Park, since the owner of the park by the number, often to Yangzhou to sell paintings. And Li, Jinnong, Zheng Xie and other exchanges, Gong poetry and painting, good plum, blue, bamboo, chrysanthemum, pine, fish, pay attention to the division of law tradition and good fortune, can own style, the brushwork vigorous Old thick, cut simple, informal shape, lively and lively. Was listed as Yangzhou eight strange one. "Bamboo Tree", "fish map", "Mexican map" and other handed down. The "Plum House Poems." Good painting pine, bamboo, orchid, chrysanthemum, plum, miscellaneous flowers and insect fish, but also to people, landscapes, especially fine plum painting. Works of bold and bold, ink dripping, rough headset, no line of rope ink, intended to sinomenine, Bai Yang, bamboo foolish. Painting plum thin hard to see, the old stem new branch, 欹 side Panqu. Plum with a printed means between〗 〖, the famous poem Mei poems are not broken〗 〖not break the sentence of the sentence. Also like to draw the wind in the Shochiku. Work book. Can poetry, descendants of a series of "Plum House Poetic Grass", only twenty-six, most scattered in the painting.

Yongzheng six years (1728) Yong Zhengdi to update the official, the implementation of the national recommendation, Li Fang Ying to "virtuous founder" by the recommendation. The following year, Li Yucheng to the capital report, thirty-year-old Li Fang Ying's father to Beijing. During the meeting, Yongzheng emperor pity Li Yu 鋐 old, asked: a son and you come with it? "Said:" The fourth sub-Fang Ying with. "Q:" What position, and wins the official no? "Said:" Health members also, of Gan, not official. "Yong Zheng laughed and said:" There is no school adopted son and married. "That is summoned, special purpose to pay in charge of Henan, Shandong's Hedong Governor Tian Wenjing assigned to the coastal magistrate.
Yongzheng eight years (1730) Li Fang Ying Shandong any magistrate. The occasion of summer and autumn, Le-flood disaster, 10,000 drift oars, the situation is pressing. Li Fangying without the approval of his boss, opening the relief, ordered the use of inventory imperial grain 1,200 stone, to work for the relief, recruiting people embankment, alleviate the disaster. But then open the official position by the Green House impeachment. Governor Tian Wenjing did not care, but praised Li Fang Ying courageous, active in the people. After the disaster, the field study, Li Fangying wrote "Xiaoqing River", "people want to view", "Shandong water control glimpse" and other works. Yongzheng ten years (1732) due to power promoted to Juzhou know state. Yongzheng twelve years (1734) he was appointed to return to any county magistrate, the same year the winter changed to Lanshan magistrate.
Yongzheng thirteen years (1735) because of his opposition to the new Governor Wang Wenjun's reclamation order, the letter straight defects, angered his boss, was dismissed from prison, became shocked the ruling and opposition parties' Lanshan injustice. People outcry said: "public for the people so convicted, please Circulation prison", Lanshan, Juzhou farmers in droves, bring their own chicken millet rice wine to visit Qingzhou prison. Jail officials can not see, the people brought the money and goods, food thrown into the prison walls, the wine jar left the prison door and corridor are blocked. This miscarriage of justice, a drag for three years. Until the first year of the Qing Emperor Qianlong (1736), Qianlong pursued the case of reclaiming the land of misfortune and care for the people, strike Wang Shijun, was vindicated. Two drums that day, the instrument reached the Qingzhou, the night Li Fang Ying was released. Li Fang Ying into the audience, standing in the military room Dan Chi Xihuai tree, the University of Zhu Shi pointed to the Minister of the king said: This is to discourage reclamation of the magistrate Li Lanshan also. Those who want to see and squeeze not to the front of the person, to hand the amount of far looked at: that is thin and long, the eyes of God who is it? Shao Zongbo Zhao Guolin and Li Fangying's father was the same year Jinshi, holding Li Fang Ying's hand, said: "Li Gongnan have children carry on." After the audience, the appointment of the magistrate to Anhui, Li Fang Ying to return home to take care of his mother and not take office.
Qianlong four years (1739), Li Fang Ying parents have died, mourning in the home for six years. Obeying the expiration of orders, ordered the buried hill county magistrate, the right to know Chuzhou House, soon transferred to Hefei magistrate. Then again famine, Li Fangying in accordance with past practice, custom relief measures, and refused to "honor" boss, was jealous, prefect plus unwarranted "corrupt" charges, dismissed from office. Before and after the magistrate to do two decades, actually three times for the prefect of the trap, Li Fang Ying said with emotion: the Han Dynasty officials, prefect of the; later officials, prefect bad.
Li Fang, after his dismissal from office in Nanjing, lived in Jinling (Nanjing) by the park, since the owner of the park by the number, often in Yangzhou to sell paintings for food and clothing, he wrote a poem in his later years: "I am no field often begging rice All the time selling plum, "painting often seal" for rice mouth "of India. And living in Nanjing, the great poet Yuan Mei and seal carver Shen Feng had very close, often side by side travel, when people call it "three cents out of the hole."
In Nanjing, Li Fang Ying also met with the sealant Ding Jing. Ding Jing arrogant group, when the daughter of a rare Indian, but Li Fang Ying Ding Ying has been donated several party India. Some people find it very strange, Ding Jing himself in the "Indian Postscript" made it clear: Tongzhou Li Fang Ying Qingjiang, painting Mei, proud uninhibited shore. The ban on official residence Jinling Xiangshi Park, day and Shen Fu Luo, Yuan Zicai swim ... ... to love the poem, as the number of printed send, talk about a spring gift.
Nineteen years of Qianlong (1754), sold in Nanjing for five years, Li Fang Ying due to physical discomfort. Seriously ill, had managed to book Yuan Mei: "Fang Yinggui two days, sick Benedict!" This will be born out of the background and the situation was only son of your son. Fang Ying without smell, the borrower of the text in the quiet palace can be almost! September 2 Bai Bai. " This is asked to write the tomb of Yuan Mei. Until the Yuan Mei received this must pen, Li Fang Ying has died many days. According to the messenger said: "This is the day before the death of our Lord, Yuan Yuan propped up, force disease book also. (1754) on September 3, this year he was 59 years old, was the "choke disease" (esophageal cancer), the doctor said: "This Huaiqi negative gas, Yu and Shu of the non- Medicine can also flat. " Before his death, he wrote down his life in the coffin of regret: "Wu Si lack of pity, I Xiwu hand!
Li Fang Ying good painting pine, bamboo, orchid, chrysanthemum, plum, miscellaneous flowers and insect fish, but also figures, landscapes, especially fine painting Mei. Works vertical and unrestrained, ink dripping, head disorderly service, no line of rope ink, intended to sinomenine, white, between bamboo foolish. Painting plum thin hard to see that the old stem new branch, 欹 side Panqu, the famous poem Mei Mei "not broken not broken off" sentence. Also like to draw the wind in the Shochiku. Work book, can poetry, the descendants of a series of "Plum House Poetic Grass", only twenty-six, most scattered in the painting. Handed down the painting as a "bamboo wind map", "fish map" and so on.